For a punt right now, Montenegro is about one of the worst places to invest. If you're not interested in the investment potential of your purchase, and you really want to buy a home there, then fine. Otherwise, avoid it like the plague.
Things to bear in mind:
1. Ethnic cleansing, be sure that what you are buying has a history of ownership that goes back far enough to protect you.
2. Lawyers, be sure that they are in your corner and not in the developer's corner.
3. Currency. Montenegro effectively doesn't have one. They use the euro, but it has no actual formal role there. If a country is so screwed up economically that they can't even sustain a currency, is that somewhere you'd like to invest?
4. Earthquakes. Not a major problem with well-built projects, but have been known to flatten whole towns.
5. Rent. Season is short and rents are very low, and hard to get unless you live there and can manage them. If you live abroad, you may find that all of your rent and even some of your own money disappears in taxes and management charges.
6. Access. Apart from the Dubrovnik link across the border, the airports in the country itself seem to operate sporadically.
7. Price. As previous posters mentioned, prices are way too high and nothing is moving. Gains that people feel that they have made may be hard to realise in reality.
8. A creepily corrupt country that has thugs (locally known as war heroes) at every level in society
Well, would you prefer my advice or that of a sales agent?