calling me "impartial" would be hard, however: I never used amithlon but AFAIK it might be difficult to find a proper kernel to support all moden hoardware out there, but here others (like Fishy_fis) might be better suited to make suggestions and give hints. For what it concerns user experience, however, it should be the nearest thing to a "steroid-powered" Amiga computer running OS 3.9. You'd be stuck to 68k emulation however.
I'd tell you to try Icaros Desktop coupled with Amiga Forever. You can buy the value edition (the most cheap one) of the latter, while the former is free, and look if it fits your needs. Icaros automates the phase of setting up the emulation environment for UAE and makes integration easy, and once you've installed Amiga Forever you have just to choose wether to run 68K emulation at startup or not. The good thing about AROS is that you can also run AROS games and applications along with classic ones.
Any choice you make, just pay attention to supported hardware. AROS runs very well on any modern processor, but support for peripherals, network and sound may vary. If you have room in the A2000 case for a pci-express video card, choose a Nvidia one, possibly GeForce 6, 7, 8 or 9.
