What are the difference in the lowers? i.e. class I, II, and III

Thanks

I beleive it's pretty much like the uppers; machining for weight.

I am new to FAL's so which would be better?

I assume you are talking about the upper receiver... as the upper receiver of the FAL is regulated.  I als thing you are confused when you mention Class as FALs are refered to Type 1, Type 2, or Type 3 receivers....

The differences are mostly cosmetic...

Here are some images that I have collected from the web that show the differences...

www.quarterbore.net/forums/showthread.php?t=191

True to AR15.com form...  I have all three FAL receivers to do my builds with...

Good Luck!

if you ARE wondering about the different types of lowers; further down QB's site's FF link at POST#68 Rooster shows the 3 standard-metric-lower recoil shields. other lower variations would be selector markings and some have lightening cuts also but the recoil shield of the lower is what will or will not 'match' your receiver. not to say it won't FIT as any lower (including inch pattern) will fit any upper
none is really any better or worse for the recreational shooter IMO
i try to match my kit's lower when building but prefer the looks of the type 2