Normal releases come out every six months, so there's a new one fairly often. LTS releases come out every two years, and are fully supported until the next LTS release come out, which means they are usually much more stable.
Are you serious on this one? The difference is 20MHz. It's not going to get any bit hotter between 1000MHz and 1020MHz... P3's could get away with a heatsink without a fan. If you're worried about heat, get some case fans.