Mic pre-amps are like seasonings; different people like different flavors. For the most part, you get what you pay for in terms of quality (i.e. a $300 is not going to compete well with a $2000 pre) BUT a cheaper one might be just perfect for a certain song/style/instrument/singer . Let your ears tell you what's best for you and your particular situation - let the opinions of others guide you as to what you use your ears on. If your opinion doesn't jibe with theirs, don't worry about it. Just go with what sounds best to you.
Scott