I think the reason the Ares BTR's went on sale the last few months is the model was upgraded, that's an assumption of mine, might be true, might not be, but it seems to be a trend.
I know my older Ares BTR 4.5-27 could have better glass, it's okay, better than some other scopes I have in the approx price range like the SWFA 3-15, but my Midas TAC's have more pleasing glass than both??!!
Sometimes these scope Co's make improvements but don't make a public statement about it. Could be the same with the Burris. I like both the Ares and the Burris, definitely prefer the reticle in the Ares, and definitely the feel of the Burris with a nod going to the Burris overall. I have no reason to doubt the Ares, all of them have functioned fine but Burris has a great track record. Though to be honest I met a guy at our local LR spot that sent his Burris 5-25 back twice and was very disappointed in it because it wasn't fixed to his satisfaction.
I know if the TAC's had the same .2 reticle as the Ares, I'd be selling a bunch of scopes and just settle on the TAC's. It's just a top scope in it's price range considering what it offers.