It is hard to say who makes the best. I think they are like any other heater they all have there horror stories. I went thru several of them. I finally went back to glass heaters. Also I never had a fish or pleco get burned by one.
For quality Eheim Jager heaters have a good reputation, but you would have to make or buy a heater guard separately. There is much buzz about the titanium heaters with external controllers these will never break though again some require you to make or buy a guard and the more expensive include it.
Have you ever considered an in-line heater? If you use a canister filter they can be plumbed in the return line. The Hydor 300wt ETH is what I use. It gets the heater out of the tank so you have more space, gives more realism, and is safer on the fish. The only downfall is that it is set up for 5/8" tube so you may have to do some plumbing mods to work it in. I am installing two of these heaters on my 210g project and have to custom plumb them into two FX5 return lines. A bit of work but well worth it not to have to look at heaters inside the tank.