The fittings should all be G1/4"... hard to say what comes with that Thermaltake though, and what size of tubing it's using (do they sell the same cooler minus the case? Info should be there).
Between those two, It's hard to say, they say the same thing... I'm not sure if "mostly copper" means the tubing is copper, but the fins are aluminum... or there's actually aluminum *inside* somewhere (which seems retarded, but who knows).
Don't go by what some retailer says, go by the manufacturers website, or reviews that have actually sacrificed one.
... personally I'd take the XT45... simply because of the dual orientation.
But, I don't like either of them, this
Is probably the one I'll get when I do... because it says Brass/Copper for "wetted materials"... it's also one of the few that's 140mm wide. (which means I can mount top or front... a bit more critical when I was still looking at single 140mm ones).
XS-PC makes good radiators, Swiftech makes alright ones.
Regarding fittings, unless you go with swivel ones, quality really doesn't matter (within reason).