chenw :
True unless he needs to upgrade his PSU to support his second 760. If he needs to, 970 is more cost effective.
Microstuttering also depends on the game, but generally older cards have more SLI related problems (970 SLI for example does not seem to exhibit it, at least not from the games I tried).
I have never seen microstuttering on any SLI build where the card costs was above $150.
560 Ti and above
650 Ti Boost and above
760 and above
Actually since the 5xx series, I have not seen MS at all as all the cards that would be suspect don't have the feature.
As for scaling, consumers are oft misled by reviews which average scaling over a whole bunch of games. The fact is that scaling is high in demanding games (new or old) and low in games that non demanding games.
Crysis 3 - 87.5% (76.5 / 40.8)
Tomb Raider - 93.3 % (111.0 / 56.9)
Compare that with Diablo 3 47.4% (360.3 / 244.4) .... but who cares when ya already have 200+ fps.