I love ALT's/BT's and my list is growing as I try to complete the two lines but I'm not into peeing comps so no numbers or lists for me 
I will say though that one of the main reasons I love them is because their scale to MP-01 and their modern day vehicle mode with a mostly good robot mode homage to their G1 namesake (mostly).
IMHO they are the DNA to our great Masterpiece line that we enjoy today, also I think that BT is better than Alt's but some may argue otherwise (I don't play with mine so paint chips are no problem)
I still function.....................while killing threads. ;-)