Bruce is a very talented guy, but you have to wonder what plug-ins he's talking about. There are a few I use in TDM that aren't available in RTAS, but not that many: Sound Toys (formerly Wave Mechanics), McDSP (don't have the OS X versions but I need to), and Access Virus. That's pretty much it.

I guess there are a few that run on HD only, so maybe that's what he means.