Personally, I advocate both raising and limping some fraction of the time. I think the key is to achieve 1, 2, 5+ opponents, then play accordingly. Without any knowledge of my opponents, I usually limp EP here and if it is not raised behind me, then I presume no one else has TT+ and play accordingly. In multiway pot (>=3 opponents) and more than one overcard, I check fold under usual circumstances. With only one overcard I will usually bet to see where I stand unless there are 4 or more oppnents. At my level: 2/4 and equivalent BM limits, people love any two cards that add to twenty.