The A600 was my first Amiga also. Going from an A500 to an A600 is a small step, you get internal IDE controller, easy step to get 2MB chip and PCMCIA port for a cheap NIC option but apart from that it's not more than an A500+ and it have limitations that until recently was hard to get around.
I'm talking about CPU/Fastmem (and other upgrades)... this have been the Achilles heel for the A600 until the ACA630 hit the market, still available I can honestly say I recommend the A600 to anyone who's knows it's limitations and still concidering it but budget an ACA630 into the purchase or you'll feel duped pritty soon. With that said get an A604 (or A603) chipmem expansion while you're at it and you'll get clockport as well as a possibility to upgrade with a scandoubler when/if the need arise.
In short, you get a lesser machine than an A1200, no AGA and with an upgrade path that is very narrow and again more expensive than the A1200. But it is also a computer that takes up less space so if you got the money I say go for it ALSO... as in get an A600 AND an A1200 and I'm sure you'll be happy with both.
