I have a finnex 50-watt in my 10g and I like the way it looks. I love the external thermostat. I don't love that I have to program it about 4 degrees higher than I want it to heat my tank to. Yesterday my tank also randomly heated to 80 degrees, no good at all for my celestial pearl danios and red cherry shrimp. I've had the heater set to 80 since I got it and it kept the temp at 74-75 but all of a sudden it's up to 80. I've had the heater off since then and now it's down to 76. The temperature in my house has been the same, so I don't know what's up. Did it randomly re-calibrate itself to work at the set temperature? I dunno.
If it were $5 cheaper for the 50-watt I would say yes immediately buy it, because it does (or did? I don't know!) keep the temp consistent better than the Hydor THEO heater I tried first did.