I work in the real estate industry, specifically a mortgage broker.
First a note to Chperplt: You can invest that $100 a month at 5% per year and in 20 years you will have $41,103. If you are smart and get 8%, that money will be $58,900, at 12% it will be $98,926. So your 20 year old brother in law was right, unless you make some pretty pitiful investment decisions, and I am not even counting the tax savings you give up by paying off your mortgage first. You would do well to seek him out for financial advice in the future.
1) I can tell you that condos are never going to appreciate as fast as a single family residence (SFR) with VERY few exceptions. They also stay on the market longer in all markets except NYC, SF and LA. Generally what you pay in an association fee will pay for a lawn maintenance co.
2) Loans on condos and townhomes are riskier than SFRs, and as such command higher interest rates, sometimes as much as a half a point. The association rules are generally reviewed by the underwriter to evaluate this risk.
3) You are much better off paying off your higher interest loans (read credit cards and cars) than making extra payments on your house. Your mortgage will most likely be your lowest interest debt (except a 0% car loan) due to the fact the interest is tax deductible. The effective rate of interest is your interest rate times (1 minus your marginal tax rate). Pay off anything else that is higher than that effective rate first.
4) Best of luck on your purchase. When you go to secure your loan, pay the most attention to the Truth in Lending statement. The loan officer will try to brush over it, but the APR on that document is the true cost of the money. If it is significantly different than your quoted rate, you are getting screwed on fees. I cannot stress this enough. That is the real number, everything else is hogwash. They will do all they can to convince you otherwise, but don't fall for it.