Just a note of my experience. I have had a BM100 running for about a year and a half at this point. It pulls out good skimmate and I am pleased with the production. It sometimes stops sucking air, but I can often blow into the tube to make it continue again. A few times I have had to disassemble the skimmer to get it working again.
This is where the only issues I have with the skimmer is. I like it's small base, the energy efficiency, the thickness of the acrylic and the production. However, taking it apart is both a pain and hard on the skimmer.
The pump's locking 'nut' has had one of the handles break off while spinning it with very little force. The plastic screws that hold the base are slowly getting stripped so it will be soon difficult to open the base. And the black base (they might be white now) Has cracked and is just holding on through pressure now.
Other than this, it's still running well. I just want to mention the longevity may not be the best (especially if one of the parts that will break on yours is essential unlike mine), but for the price you really can't beat it.