Lots of schools have it. A=4.0, A-=3.7, B+=3.3, B=3.0, B-=2.7. Repeat this pattern over and over. Also, +/- normally doesn't change difficulty unless the class is curved (b/c it'll become more competitive as profs. can section students in one range off into +/flat/-). With that said, at Tech, you'll probably get a solid share of Bs, whereas at UGA, some B+s/A-s (in curved classes where you are doing well, but not necessarily at the top, an A- may come as a pleasant surprise) may be helpful (on the contrary a B- maybe hurtful, however, this is generally the average at +/- schools, whereas Tech may give a reasonable amount of Cs). Basically, Tech will probably still be harder. It's hard to look at grading and tell, but you know it'll probably be more rigorous and competitive.
There are two reasons why people complain about the plus/minus system:
1) There's no A+. They think that if there is a B+ and C+, there should be an A+, but that it should be something like a 4.3. You should get rewarded for having a grade that high.
2) There's a C-, but C is a passing grade for major classes. Therefore, a C- is almost practically an F. Some teachers get away with this by refusing to give away C-'s.
The plus/minus system hurts and helps you. It helps you if you get a B+ or a C+ (instead of a B or C), but it hurts you if you get a A-, B-, or a C- (instead of an A, B, or C). I'm not sure how it has affected our average GPA. I'm also not sure what Tech's grading system is like, but just in general, Tech is reportedly harder than UGA.
It's A,B,C,D, F, no plus/minus at Tech. That's not what makes it harder though. It's just more rigorous and since most classes have low averages, they curve up some, but it is often not as generous a curve as you would see here for example. At Emory, we consider a C- passing, but you should enter the next series of a sequence w/reservation if you get one in the first. Also, getting a C- is generally considered failing b/c grades in harder classes are usually curved so that the average is a high C+/B-. Like if the average in Weinschenk's orgo class is a 65-70, this is recentered to a C+ or B- depending on where the median is (and normally it's really close to the average so the average and those around it get a B-), so you know if you got a C- after a curve like that, you were doing pretty poorly. You have to have like a flat-low 50 or somewhere in the high 40s. C- is also bad/seen as failing in the sense that many classes grades are indeed inflated like that or worse (it kinda makes sense for Dr. W to do it b/c his exams are far more difficult than others except Soria). The flat C/F grades become kind of rare in such curved classes. However, those where regular grading scale is applied have plenty of C grades at least (though few D/F grades). The pre-med science classes for example give plenty of C grades. The ones that are more major specific upperlevels (non pre-med weedouts) however give much less.
As for humanities/social sciences: If you get a C-, something is wrong. Anything below C+/B- is indeed sketch.