I'd have to chime in and say yes, get a USGI M1 if you're going to get another one. If you want it to LOOK good, get a new stock, and have the whole thing reparkerized. You'll probably still spend less than you mentioned.
I've seen the reviews of the Lithgow receivers, but would like to mind everyone, ONE receiver that looks like crap doesn't mean that ALL of them will be. I've heard stories of CAI M1s falling apart, or having only hand-tightened barrels, but I've heard at least an equal number of "I've got one, and it works fine" stories.
If you seriously considered buying a non USGI M1, it's certainly not going to be worth as much as the price you listed above. Ask the seller if you can have it checked by a competent gunsmith. Of course, the reputable M1 smiths (Orion 7, Fulton Armory, DGR) won't TOUCH a non USGI rifle.