Off of the top of my head, here's basically what you're gaining and losing to a switch:
Advantages:
- Pretty sure you can transfer your home number to a cell phone, don't quote me on that though
- Can take the phone anywhere and it should work
- Caller-ID Included
- Voicemail
- Long Distance is "free"
- If the tower goes out, phone may still be used by another distant tower
- Going to be supported for ages given the current trend of people wanting to go Wireless
Disadvantages:
- Sound quality is lesser on a Wireless network
- E911 services will have a more difficult time identifying your location via a cell phone, over a fixed landline
- Eats into your minutes (exclude if you don't have unlimited local)
- Not a regulated service, so there is no requirement to promptly restore service should an issue occur with the tower, and no expectation that there will be adequite capacity to meet calling demands
- You may be living in a poor reception area
I suppose you can add more to the list, but this is all I can think of quickly
