In summary, you get what you pay for and you better understand what you pay for.
I have used Bumblebee twice - in 2010 and 2014. Both times we got a very reasonable fixed rate so we were happy. Both times, the crew (mostly very young guys) busted their you-know-whats through the hot weather and narrow staircases to get the job done. I felt guilty that they were charging so little. The second time I used them, they called in another crew (that had finished) to help out with our job, so they can speed it up. That was great. They did drop and break a chest-of-drawers.. and luckily it was a piece I cared little for - but that was just dumb luck.
The bad: Both times there was a member of their crew who wasn't pulling his weight.. the first time the older guy was more interested in chatting than working while the young guys were dripping in sweat. The second time the oldest guy in the crew (maybe 25yo) was taking so many breaks that one of the young guys eventually told him off. Sadly, the 25yo collected the fee and tip - I hope he shared it around.
Bottom line, you get what you pay for - some damage to the walls, something broken, but a crew that works hard for a good price.
Would I recommend them to someone looking to save? Yes
Would I recommend them to someone who is looking for a tender-touch mover? Probably not.. expect to pay more