I recently picked up two of Vir2's products: namely Acoustic Legends HD and Elite Orchestral Percussion (E.O.P). I can't say I was genuinely impressed, but I was astounded at the selection and variety of instruments included in EOP. I am still having difficulties getting a nice orchestral sound out of EOP; it seems that at higher velocities, the instruments get a "tinny" sound (as if a hi-pass filter is being used).
One of the things emphasized in the EOP advertisement is the sample engine. This is the ability to automatically call up pre-configured loops within the Kontakt interface. For example, you could turn on a 16th roll loop by pressing the keyswitch C0. Frankly, I never found myself using these features as they took out the fun of making your own percussion part. I imagine they would be useful when in a pinch for movie scoring.
Another feature is the reverb. It's called EZroom, and it's included with all the patches. It's your basic reverb, but the reason they say you should use it is because the tails are recorded from the same rooms as the samples. Anyway, it's your choice in the end, and I found that Altiverb 6 sounded a lot more real than the EZroom. Maybe it's because I'm more familiar with that interface...
Acoustic Legends HD is actually amazing for what it is. Having used Realstrat Guitar, Podfarm, and others, I can say that this one beats them all. The strumming requires a lot of fine-tuning (with velocities), but once you take the time, you can barely tell the difference from normal recordings and the sampled stuff. My biggest gripe is the space it takes - almost 40GB! On my 265GB drive, it's a huge chunk!