A1200 is an easier option if you ask me. They are easier to find and don't cost a fortune. Also CSPPC's (if you're looking) are weaker in design lastability-wise compared to BPPC. Most peripherals are easier to obtain on A1200 than on an A4000. And less messing with jumpers on an A1200.
For hardcore upgrader who wants to get rid of a wad of cash I recommend an A4000T
. Make no mistake, you can put a lot of money on an A1200 too if you like expanding/tinkering.