Finnex ones are pretty good. I think they have a separate temperature controller you can buy as well. I just hate having equipment in the tank itself unless it's glassware, so I'm a bit biased when I say look into the Hydor ETH in-line heaters.
I agree with freph if you want less equipments in your tank , spend a lil bit more and get the Hydor In-line heaters. It s really worth it. I have 2 on my 180gals and they keep stable temp. (If you buy one get the 300W , it s not hurting anything to have extra power and just in case you may want to upgarde to bigger tank in the future-just my 2 cents)
If you want something afforable and really don't care what you have extra in your tank. I would receommend getting heaters from Via Aqua. They are cheap and working as good as the expensive ones. I have one for my discus grow-out tank and have no prob whatsoever so far.
Happy planted tank