Well they are complete different phones. The Maxx HD has a much larger screen and is 4G. The 4s is only a 3G phone. I'm not sure how these 2 even come up in the same discussion as choices. Honestly I would not "upgrade" to a phone that isn't 4G. Of course I wouldn't upgrade to any Apple product to begin with.
No I do not I wish I would have stuck with the droid. It shuts off when it wants. I go through 3 charges a day with the battery. This is not my work phone. I am not on it either.