What do you want to do with APRS?
I've tried that AGW Tracker and can't say I ever got it to work, so can't tell you anything useful about it. I also use APRSISCE, and can say that if done correctly, it does work well. Same for UI-View, but that's not so easy to set up.
I use APRS strictly for RF tracking, no particular use for the internet stuff. I started with UI-View (real pain) and have more or less switched to APRSISE. Actually, use both of them, depends on what I'm doing at the time. None of this is strictly using the radio, I use a laptop. The radio may do it all, but the laptop just offers a larger 'screen' and more information in a more usable form (in my opinion).
I'm not aware of any one program that offers/furnishes everything needed/required for people to do everything they want to do with it. I think such a program isn't going to be 'free' by any means, and it isn't going to be a 'small' program either. It would be very nice is someone wouold write such a thing, but I don't think I'm gonna hold my breath. Oh well...
- 'Doc