I haven't played on any BLD fields, but I did stop by the ones in Vegas and look around. I'll list what I liked and didn't.
Like: Beautiful fields. These truly are top notch. Nice dugouts, landscaping and stadium seating. Pro shop that sells all sorts of good stuff (though overpriced).
Didn't like: Gate admission, no outside food or beverages, you have to buy THEIR crappy balls at (I think) $5 each. Fields are also too small. These parks are like 280'.
Overall it's a spiffy facility, but to me the costs outweigh the benefits. It just isn't an economical place to play softball. An occasional tourny there wouldn't hurt though.