1. grammar-wise it is similar to slovenian as far as complexity goes (although it is a little bit less systematic, true). but i bet you havent ever heard more than a few sentences in slovenian, let alone eg. slovak or polish
2. but comparing to russian, the latter is more difficult according to several guys who speak both. including my gf whos parents are serbian and studies russian.
3. you "failed" to mention croatian, which is according to almost all modern linguists (except for croatian and serbian ones) the same language as serbian (the literary norm, not dialects). okay it has differences both in grammar and spelling, but those are minimal.
4. there are languages with so much different grammar from slavic languages, it is (in my opinion) pointless to compare
5. cpBuja tIIu IIpcTa
6. you're trolling a little :D