Cove heaters are pretty generic- pick one compatible with the decor of where you plan to install them. Most people are OK with the look, fit & feel of the standard lineup from King Electric, but IIRC they only come in one color (almond), which doesn't work with everybody's color scheme.  TPI/Markel probably sells more units into commercial & office environments where white/off-white walls & ceilings are the standard.

Look carefully at noise specifications when selecting any heaters with fans- some are really obnoxious. Also look out for recall notices and be VERY careful about mounting instructions for any in-wall resistance heater.

I would not take a cove heater as a gift as they are crude convective heaters "designed" to be installed at the ceiling, the least effective place one could use. They should be reserved to address serious mistakes in the heating design process.

BadgerBoilerMN

What is your opinion on electric hydronic baseboard heaters?

Low.

They were made at a time when the old hydronic guys thought they could compete with the newfangled "forced" air heating systems, which Mr. Carrier made with cooling included! They were wrong but the fin-tube remains.
I have often said that fin-tube is used by folks that can't afford to be really comfortable.

I have to admit that hydronic fin-tube baseboard can be more comfortable than scorched air if it is properly sized and installed at the perimeter where it properly bathes the cold exterior walls eliminating those cold ghosts running all over poorly heated homes everywhere.

The advantage of a radiant cove in a low-load room is low fire hazard and faster response time relative to typical electric baseboards, and they can fit over both windows & doors. They don't really cut it as a solution in a code-min house, but can work reasonably in a higher-R house. In some situations (including higher load situations) a low-mass electric panel radiator works out better than a cove heater, but they're typically more money too.

In fordman460's case the design heat load of the doored off rooms is 3-4K @ -5F or 0F or whatever the design temp that was used for, which means the rooms are nearly self-heating at the average mid-winter load, when occupied by 2 conscious humans using some lights &/or electronics. The mean outside winter temp in zip code 80003 is about 30-31F (see; http://weatherspark.com/#!dashboard;q=80003%20usa ), which means the average loads of those rooms will be 1-2 KBTU/hr, and largely supported passively by the mini-split in the adjacent space.

Or you could set next to a reading lamp turned to the third click :-).

We agree Dana, radiant cove heaters make good sense in energy efficient buildings, especially if some of the rooms are not occupied full time. You can significantly reduce heating operational cost by using sensors to detect when the rooms are occupied and only provide heat when the rooms are occupied. Radiant cove heaters don’t make much sense in poorly insulated and sealed buildings…but then these type of buildings really don’t make much sense either other than if the building is on the historical register…in which case it likely has nice radiators that should be retained. And spending a fortune on a heating system remodel in a building with a lousy envelope makes even less sense. Sometimes it makes more sense just to move…