Basically, the borg and the replicants are the same. The differences are marginal and have only been thrown in as anti-lawyer chaff.
- Both resemble humans. (Yes I know not all Borg are human but all are humanoid species. And yes I know replicators 1.0 are lego-brick insectoid. But the more threatening evolution, replicators 2.0, look human.)
- Both are more-or-less hive minds. Not completely, there are some points with both which mean they have some residual individuality (sp? just in case.) for example Replicant #4 (long ago I watched that SG epidose, so the number can be wrong. I mean the one which/who is tricked by the SG team), and the Defected Borg in ST:TNG.
- Both are surprisingly vulnerable to chemically-propelled projectiles (ie those in use with today's firearms).
- Both don't really 'think' -- they seem to compute, but their thinking is very linear and predictable. However, tapping external sources (ie Data, Carter) to overcome their limitations is on both agendas.
The differences between the two are more or less dictated by the different settings. ST:TNG tried to continue (and to improve) on the ST Classic and ST: Phase II storyline, while SG didn't want too big a jump forward. Mankind wasn't supposed to master FTL travel, space-manipulating devices, matter transmitter tech, etc. within the scope of the SG series. The story was set around a rather small team utilizing some alien technologies in about the same way as "cavemen who happen to find a revolver." Not that I'd find that approach unfunny though.
IMO, it's irrelevant whether the Borg or the Replicators win. In the end, they will merge into one more powerful enemy with their combined abilities.
