Submersable vs External which way you go??

[Slick Fork]

One of the big reasons I think people go for the externals is heat issues. Personally, I went for a Hydor Seltz L45. Low power, good flow, good price. I'm running it submersible because I seem to have the opposite problem... my tanks in the basement and I struggle to keep it close to 80, most days it's further down in the high 70's so I'm after all the heat transfer I can get!