Solar panels of both types are very efficient at converting the suns energy, the main gripe with them (for me) is that they provide an excess of energy when it's least required, ie too much hot water in a summer, and little in a winter when you need it most! In the summer Months i know many locals that simply use a long black hose pipe in the garden for their needs.
I can't vouch for Topolovgrad but there are plenty of suppliers in Burgas so can imagine it will be similar in your town, tho it maybe best that you see some working examples to get a feel for there performance. and they aren't so expensive to buy and fit. I'd be interested, should you fit them, of your results and degree of satisfaction.