According to google maps it would take you 40 minutes from Preobrazhenskaya and 50 minutes from Elektrozavodskaya.

Neighborhood is OK, I don't think there's much difference. Red metro line is very quiet, not too many people even during rush hours. Don't know about blue line.

There're plans for 2016 to build new metro line that would make your way from Elektrozavodskaya a bit shorter (probably much shorter, but I can't give you exact numbers. It would be 30-50% off, I guess). I don't know long it would actually take them to build it, but you probably should take it into account if you're planning to stay in Moscow for 5 years.

Also Elektrozavodskaya is a bit closer to the center. It would take you like 3 stations to get to the Red Square.


UPD: actually google maps counts incorrectly.
Real numbers would be:
Eletrozavodskaya -> RGGU — 28 min. + 10 min. for you to get to metro
Preobrazhenskaya -> RGGU — 28 min. + 10 min. for you to get to metro

So it's exactly the same.