I quite enjoy MLS myself. It's been a better developed league than a lot of European based football fans will give it credit for. Everything that the Yanks got wrong with the old NASL they corrected this time with MLS. The league's commitment to creating community based clubs with their own (impressive) custom built stadiums is noteworthy. In terms of standard of play I'd probably equate it with the Championship. It helps that, with one exception, I can watch any game with a complete neutrals head on also.
The area of the US that seems to have the best grasp of European match day 'culture', so to speak, are the NW clubs. If I was to ever attend an MLS game then I'd prefer it to be in Seattle or Portland. They seem to really get the whole club identity idea better than many other areas of the US.