I have lived in Bahrain few years ago, and loved it. It's more like living in a convenient village and Bahraini people are known to be the friendliest in the GCC. Cost of living is similar to what you pay in Doha and house rental is little cheaper. Now I know that Bahraini companies do not pay high salaries, So if your salary is 10,000. QR in Doha than you should compare that to what you might get paid in Bahrain 1,000. BD.
I haven't lived in Kuwait, but I visit there often and friends tell me "like living in between Saudi Arabia and Qatar" when it comes to modernization and freedom!