I love and hate my Eris at the same time. When it works, it's great. It's a bit slow (sometimes a lot slow), but I can look past that considering the price. What I can't look past is the overall buggy nature of the phone. Seriously, it is literally the most unpredictable, buggy device I have ever owned in my life. Is it Android 1.5 or Sense UI? Sometimes it won't call out, sometimes it won't turn the wireless on, sometimes it won't turn it off, sometimes the keyboard won't work, etc. etc. A reboot fixes everything, but give it enough time and it will start freaking out. I have to reboot at least a few times a week.
I am a very forgiving person when it comes to technology. I'm an engineer myself and I realize how difficult it is to make a piece of software that is perfect and runs on many different platforms, but seriously it should at least get the basics right, and sometimes it just doesn't (like when it refuses to make a call). I'm hoping that software updates (and the upcoming upgrade to 2.1) improves things but for now I simply couldn't recommend the Eris to anyone looking for a smartphone that just works without any hassle.
All that being said, a friend of mine just got a Nexus One and  is it a beautiful phone. Blazing fast with a great interface, easily as nice as Sense.
I can tell you that the HTC Hero from Sprint (Still sitting on my desk, waiting to be returned at some point in the future when Sprint, I, and the Iowa Attorney General's office come to an "understanding") was exactly the same way.
I can tell you that even with a "hacked, incomplete, only 90% functionional 'Nexus One; " Android 2.1 ROM installed on it, it seems MUCH smoother than the default factory ROM with Sense UI. Although I can not speak for the Radio issues you mention, as my only connection to the world with this phone is via WiFi, everything else i've tried on it. As you noticed with your friend's Nexus One, it is WAY smoother than the Eris, but if you were to play around with a Motoroal Droid after it's been up and running a few days, you would see that the Droid is just as smooth running, free of those "slow to a halt, have to reboot" issues that plagued me with the Hero when I was using that.
My daughter has the Eris, and hasn't "complained" about the laggy behavior that I know she experiences, but then again she came from an incredibly buggy blackberry, so she just might not know better LOL
Dangerous Dave, though you haven't had problems yet, I'm betting you will eventually. You've only had your phone for a month. Mine is not "defective". I know the difference between an isolated defective device and just poor design, my wife's has all the same issues. Something on the Eris is terribly wrong in the firmware. And don't tell me it just doesn't have the power. If software is designed well, it can run just fine on slower hardware. The hardware in the Eris is powerful enough to run anything Android can dish out if it's written well.
bkfist, you mention the Droid and the Nexus are quick and smooth, which is true. But you must remember, they're running 2.x while the Eris is running 1.5. And I'm not talking about the speed of everything, the Droid and Eris will always be faster than the Eris, that's not what I mean. I'm talking about simple hiccups and basic funtionality. The keyoard being slow on the Eris is not because of the hardware. It doesn't take much power to run the keyboard and crap like that, and yet it's buggy and slow. It takes forever to rotate the screen sometimes, you can't tell me a 500Mhz processor can't do something as simple as that. I'm hoping the 2.1 update or any other future upgrades will fix the issues. If they don't, I'll be GREATLY looking forward to a new phone when I'm due for an upgrade in January 2011. Like I said, something is wrong with the Eris. It's either 1.5, or the sense UI, or both. Either way, it can be fixed, I just hope they do it sooner than later, if they're going to do it at all.
My brother has a Blackberry Storm 1 which was a pile of garbage when it first came out. Slow and barely useable. But a firmware update GREATLY improved it's performance. The same can be done with the Eris.
BTW, I tried to post this from my phone, but I was having to type only about one letter every second as that's all the keyboard would keep up with, so I gave up and typed it on my PC.
Just tried to start handcent on my Eris, it took 20 seconds. That is unacceptable. Once it did start, I open the keyboard and rotated the phone. It took a good 6 seconds for it to rotate the screen and show the sidescreen keyboard.
90% of the time, a slow and buggy Eris will trace back to a piece of sh** freeware app. Whenever my Eris runs slow, I can use OSmonitor or SpareParts to trackdown the crappy app. Once the bad app is killed and/or removed... I'm back running great again. I've experienced the slow keyboard typing... the slow rotation (however, there is a built-in 1-2sec delay)... and its ALWAYS a bad app. Sometimes its an HTC app, yes.. but its usually a 3rd party app.
* I've had a huge email attachment that stalled cause slowdowns.... happens in Windows sometimes too...Ctrl-Alt-Del
* I've had a game that didnt shutdown kill my cell and needed a battery pull
* I've had SenseUI skitzout using a 3rd party wallpaper app.... everything crashed... but once removed, I was running perfect.
Long story short... I've had my Eris since 11/6 and I've pulled the battery 3 times at most. The last pull was easily 3-4 weeks ago as I know what to look for (bad running apps).
I think the Eris does have a few wierd oddities, but for the power and ability... I would never trade it in for anything else.
Okay, I am going to try an experiment. I literally uninstalled just about every app I had. There are only about 10 left, and none that should do much of anything while they're not in the foreground, and I have basically all notifications turned off for everything. I installed OSmonitor (great app btw) so if my Eris ever comes to a grinding hault again I can look at that and see what the problem is.
I KNOW the Eris has enough power to run android with sense UI, I know it does. So I agree a rogue app (or combination of several) is mostly likely the majority of the issue. Though I do believe some of it is the firmware and can be fixed with updates.
Truelove, where can I get one of those crystal balls where you can see that someone will have problems with thier phone, even though it's been fine so far? I've had mine since the first week of November last year and done 2 OTA updates and it still works fine, but to see problems coming would really be cool.
I have a Eris and there are many glitches that need fixing!
1. All my Motorolas have been able to set incoming calls so that it will speak who is calling, not this phone
2. I bought a Motorola hands free device for my car but with the Eris you cannot use voice commands, another glitch!
3. It is not easy to send pictures to my computer via bluetooth. It works on G-Mail
There are alot of things I like but these are basics that need to be fixed for the extra price of $30.00 plus $7.99 ins. plus $2.99 for visual voice mail!
Gerio, what sorts of apps do you have installed? You must not have many of them. Like I said, I uninstalled basically everything to see if one of my apps was causing the issue, we'll see.
Well, so far so good. I uninstalled basically everything and turned off all the notifications I actually care about and the Eris is blazing right along. It'll never be as fast as the Droid or the Nexus, I know that, but it's going good so far. Though some or the bugs I've seen (wireless refusing to turn on and off via the HTC widgets, keyboard not working, calls not going out, etc.) were not performance issues, so I may still see those.