Both are probably top dog on average in their respected universe. Pre-Crisis Brainiac 5 has built some uber devices (Concentrator/Miracle Machine) and can learn anything on the fly. Who wins in a prep war? Who is smarter?
Yeah, he built it from the plans that he got from the Controllers, but he did build the Concentrator from scratch, a machine that can take every joule of energy in the UNIVERSE and do what he wishes with it.
He's also bested the Time Trapper (Entropy incarnate), brought back Dream Girl from the dead, and understood the science behind the MM, bested beings that are abstract/god level, so, he's definitely up there.
Pre-crisis shenanigans, man. Beastly as Reed is - and we all know he sets the pace for prep cheese - Brainy's best few feats are just irreplicable in modern comics, because writers are bound by some semblance of logic and believability.
I didn't think it would be possible for Golgo to find a match for Reed in this "prep" series he's been doing recently. There's only 3-4 that could even make it a close match. But it seems I may be wrong.
He's not trying to find matches for anything, he's trying to make DC look better in every category (science, telepathy, etc) even to the point of forgoing sleep.
IF they did you made them that way, this one here is an example of it, you even put pro-Braniac stuff in the first post.
The crazy part is that you're doing this in ever increasing volume and blatancy. Most people would slow down after a few years but you're doing the opposite