The cool thing about the a1200 is its ability to 'grow' with your demands. At first, its just as with the A500: a cheap alternative to the big box machines that can play all those cool new games. And believe me, there are loads of AGA games that you're not able to play on your old ECS machines. Then, after some time, you run some productivity stuff and find out you want a harddrive. After that, you get an accelerator, a tower conversion, graphics card etc etc. Each time it makes the machine even better than before, each time it is able to meet your demands.
Last year I had to decide between a stock a1200 and a stock a4000/040 and in the end I went for the a1200 route, selling the a4000. Its just much more fullfilling to have an entry-level machine expanded to the max, especially when you can keep it all in its original case.