As someone new to Android, but a (former) user of the iPad, I have to say I'm mixed about the lack of access to the market.
I like the fact that the Amazon App Store is so tightly integrated in to the Fire, and that the apps that are in there are (generally) compatible with the Fire so I don't have to waste my time with apps that are out of date or incompatible for some reason. And I find the selection fairly good from the start, and I think it's only likely to get better - developer interest in the Amazon App Store is very high because of the millions of Fire's sold, so there will be a lot of apps added between now and x-mas for sure.
What I don't like is that there are some pretty important apps that aren't yet available in the Amazon store. Specifically for me there were two apps I absolutely needed; the NY Times app and Pogoplug. I was able to download both from other sources, and side-load them easily without jailbreaking, but finding them wasn't easy. Actually the Pogoplug app turned out to be incompatible, so that actually supports my first point.
Ultimately I think this is a temporary issue; most of the really good stuff will end up in the Amazon App Store and there will be tons of crap stuff too, but at least it will be working crap stuff. For those who are more inclined to mess with non-mainstream apps, side-loading is easy enough to do without jailbreaking, and if you need to you can get the Android Market on the Fire pretty easily now (apparently using
SuperOneClick works) but frankly I'm not sure I see the need at this point.
EDIT: Just to be clear, you don't actually need to "jailbreak" the fire to get apps from other places - they can be easily loaded by USB. The only problem is that the Fire doesn't have
direct access to the Market, so if they Fire is your only Android device you have to find the apps in other places. If you already have an active Market account, it is my understanding that you can use that account to download apps to your PC and then transfer them to your Fire without any problem.