Hi Bill,
I've enjoyed them all so far. The AOP carrier is possibly the most unusual with the full engine build to look forward to. I'll stick pretty much to the rear build sequence something I've altered in all the others, so yes, it was the first one I spotted but the last one I bought.
The quality of the parts has always been excellent with the one exception of the slightly short engine block in the Mk I set I think, but sure fixing it up was all part of modelling. The new instructions are very good overall so it really depends if you want one for a specific setting or something more roving like the AOP.
I've still got the 3" mtr version to have a look at, but the AOP might possibly be the most interesting of them all. I haven't used the Platoon Infantry sets, but all the sets seem to offer a number of possible finishes and styles, giving good choise of finish.
Buildability was good in all the sets I've tried so far, but even with a basic set of new tracks you can still do a nice job on the basic Tamiya kit, with a little bit of imagination.
Kinda take your pic, I have no favourite as I like this vehicle, it was used by just about everybody, everywhere. If you have an old one you could do a gutted carrier, now there's a thought lol, lol.
Cheers
Al