sigma pi vs. pike

Oh gosh. I mean, if those are absolutely the only two you are interested in- I would say sigpi has more established relations with sororities, better parties, a house closer to campus, and has decent brotherhood. They're less douchey than pike but only by a hair.

Pike is falling apart, I said say avoid them.

Also check out kappa sigma and theta chi- they have qualities similar to sigpi but a little more classy and less hazing

I rushed both of these fraternities, and I happen to know members in both of them. I'll be honest, both of them seem to "rage" harder than us which tends to give them the image of being douche bags. Pike douchebags seem to have a little more class than their Sigma Pi counter parts but they are not quite as established on this campus as they are nationally. They just got that new house and while it's far from campus, it's nice as hell. Sigma Pi is ruder to girls but their reputation is more so they will likely have better relations with all the sororities rather than a set few.
From a neutral outside perspective, I disagree with a previous comment. Pike may have taken a hit when they lost their old house but they have a ton of potential with the new one whereas Sigma Pi is solidly consistent.