Which app are you using? SIR, Waves?
I use Tascams GigaPulse Pro.
www.tascam.com I use it primarily for the reflections and harmonics from the inside of a piano, reflections created from the hollow body of an acoustic guitar,etc. I have Taj Mahal and all of that shit, but as GB said, it's just another space. I prefer the smaller ones for realism, etc.
Mic modeller, and placement are also available on some apps, i.e. placing the instruments where you want on a stage and so forth. This is where a regular app, and a well designed IR app show their differences.
Pretend your reverb is the last amount of water on the planet. Use it sparingly, and you will prefer the sound. Just listen to the people who are mixing " Smooth ( yawn, yawn Kenny G. shit ) jazz. They tend to bathe in it, which results in a cheezy," yeah I've got a reverb and have gotta use it " type of mix.
If You Had A Good Enough Ear To Use Scope, Then You'll Be Fine,