I'd say Bitstamp has a very good track record, and what's wrong with Slovenia? It's probably about on the level of the Czech Republic in terms of economic freedom, development, level of corruption (relatively low), output, business practices, etc. Would doing business with a Czech company make you nervous?
In business culture, Slovenia looks toward Germany more than toward the former Eastern Block (of which it was never a part).
I mean, Bitstamp's owners are public people. I feel pretty confident that they're not going to run off with their depositors money. Is there something else that you're concerned about?
But I agree, if you want to just buy coins, Coinbase is a good start. And Kraken is looking very good, too, particularly if you're a serious trader (that's who they appear to target).