Firstly the Good: this is a great idea and it is a very well made peice of kit. It's robust and definaty suited to giging drummer who want to either expand the playing surfaces on the electronic kit, or want to incorprate it as part of a hybrid solution. I do both. I use one on my Roland TD20 kit and I use two on my accoustic kit via a Roland TM2.
Now the Not So Perfect: this trigger fits very well onto Roland V Drums, however I've use on two differnt accoustic kits (Gretsch and a DW) on floor tom and snare, and in both cases the fit is less than perfect. The BT-1 comes with spacing adapters, but these didn't really help.
Also this is a single trigger surface, so in principal it should only need a mono jack lead, however it only works with a stereo jack which is provided. Whs is this an issue you ask...? Well on the TM2 Roland Trigger Module, you can split each stereo input - of which there are two - into monos using a 1 x stereo - 2 x mono Y cable, therefore allwing you to have four triggers instead of two.