Engine block heaters

Hello, how many of you guys have block heaters on your snowmobile? I am looking at getting some for my rigs. They have a few different types, some that heat up the coolant system and some that heat up the engine oil. I also see some that are heat pads that can be glued onto the engine oil pan. I was wondering which type you would prefer for heating up your engine. I have just used a hair dryer or heat gun to warm up the engine in the morning. Usually use a blanket or cover to retain heat in the snowmachine. Thanks!

I had a 4 stroke 07 Bearcat. The dealer emphasized that I warm the motor up before running it for 15 minutes. So I had a command start installed so it would start by temperature or by a remote. It was over an hour to the lines I trapped so 15 minutes before the trail head I would start it without stopping because I am lazy. If it was really cold I would start it twice in that hour. I also installed a small gel battery instead of the one that came with the machine. I really worried because there was no other way to start the machine!