When it comes to compatibility 030 is better then an 040.
Most likely you will have trouble running diskbased games from the first and second generation. Games that actively supported accelerators shouldn't have any problem at all.
If you only want a retro game machine I would recommend the Blizzard, when you actually want to use the amiga, I strongly recommend the Apollo 1240 (though even that could be alittle to less power to make actual use of a PCI board).
The blizzard 1230IV should give 15 MIPs while the Apollo 1240 at 28 MHz should reach 23 MIPs (estimated from a Blizzard 1240 40MHz that gives 30 MIPs)
