I think I asked this question before but may not have gotten a response.

The answer is simple: do a trial addition of a device to your Harmony remote.  Take a look at what commands you get.  You will need, of course, an empty slot for the candidate device-- a possible reason reason for buying the next model up.

Especially important is getting Power On and Power Off ("discrete power codes").  Just getting a Power Toggle (what all original remotes offer) is bad because your remote has to assume it knows the state of your devices at certain times.  You probably know that drill, using the Help button, etc.

I'm thinking of upgrading my Toshiba DVD, which likes to stop and show me an ad for Toshiba every couple of hours.  And, a big strike against it is that it has Power Toggle and Power On, but strangely, no Power Off. 

Some review spoke well of a Sony BluRay player.  But if the Sony does not have a full set of discrete power codes, I will definitely look for another model.