honestly, with reptiles i've always used the coil kind. i guess there were problems at some point with them and that makes people not want to use them anymore. i have not had any problems and use them with both of my chams. this is just me tho. my coil cost the same as the long kinda. not being chep just dont want to buy a hood. dont like the way they look on a FR. lol.
I don't really know what the difference is but Ive read that the coiled kind can blind reptiles so once I heard that I instantly returned it and got a reptisun 5.0 uvb toob with an 18inch hood