I found a sweet priced cav upper for just over 400 but I can't find any opinions(believe it or not) any input would be greatly appriciated.
Also, any particular input on lowers that match up well would be great!

I got a new Cav Arms 20" that matched up perfectly with an Ameetec lower. Fit and color are  a perfect match. There was no movement at all at first and even after 1.5k rnds of 5.56 it is still tight. The same lower when used with a new Stag upper is fairly loose so I attribute the tightness  to the Cav Arms upper. The only problem with the CA upper is the hand guards melted under the hg cap so I had to buy some YHM 2 pc aluminum. I've never had a problem with the upper itself and think it's high quality.