That partly depends on how much work you would like to do on your own. Take a look at my DIY heater at the following link in my album:
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I bought the same heater the factory installs and received not one, but two damaged units. Both had identical damage and both
obviously left the manufacturer's in the condition I received them. The damage on both was to the grill, and I even offered to change it myself on the first one if they would send me an undamaged part. They insisted on having the entire unit returned to them. The process was pretty painful and literally took several months, what with three long trips diagonally across the continent, indicating the problem was one of long duration. The second unit also looked like it would have been of lesser electrical quality since an Italian motor was replaced with a much bulkier, cheaper looking, Chinese version. The wiring had also changed from a plug-in connection at the motor to a hard-wired unit.
After I complained about their quality control and they told me they had QC as good as anyone around I told them to keep their unit and built my own. Part of their attitude problem may be that they seem to be the only source of heaters of this type suitable for small to moderate sized boats.
It is not hard, but is a bit time consuming, and cutting those holes in the liner takes a bit of courage. I am happy with the result, and it even has at least two advantages over the factory unit in my opinion: 1. The location and locker space used is better in my opinion; 2. I can use it with the pilot seat up or down.
If I were to decide on the unit the factory uses, I would still consider installing it under the sink instead of in the starboard locker where it is blocked by the pilot seat if it is down (and might even damage the fabric).