I've been a long time customer of MusicLab's guitars (RealGuitar (acoustic), RealStrat, RealLPC, RealRick) and out of all the virtual VSTi guitars I own, MusicLab creates the best sounding and best performing guitars, IMHO.
First there is the playability.  RealGuitars have the best chord variations when playing chords on a MIDI keyboard.  They offer a consistently dependable chord sound, while other companies guitars often don't play what you want unless you hit the keys exactly the right way.  MusicLab's chord play is the most forgiving, as far as timing, keys pressed, and strumming.  They are also one of the only companies that allow you to play the chords with your right hand and strum with your left.  Many companies only offer it the other way around.  And for me, it's easier to play chords with my right hand.

On to Version 5.  -   I admit the last couple of version updates were kind of "meh".  Offering not very exciting features to their updates.  But Version 5, especially if you own a previous version, for $63, it's a no-brainer.
The amount of new features (including the RealGuitar Steel String guitar, which is virtually a whole new separate guitar) is very exciting. I particularly like the "Voice Leading" feature, which allows you to play a few single notes in between chords, giving chord changes a smoother and more realistic transition effect. 

A few other new features offers reverb, better editing on velocity, Dynamic Velocity Strum, Sliding, and a whole bunch of new types of guitars including 7 and 12 string guitars.  There are a lot more new features that I haven't mentioned, and am still in the process of trying out.

All the new features, things that REALLY add useful functions to the previous versions, along with the already existing preset chord options and dependable playability, make version 5 one of the best updates MusicLab has ever offered.   As I mentioned I have about a dozen other brands of VSTi Guitars, but MusicLab's RealGuitars have always been my go-to guitars, now more than ever.  Many other virtual guitars offer more efx with their products (that is a plus) but since I own AmpliTube, Guitar Rig and TH3, it's not a big deal, especially since all the efx and amp sims don't matter if you don't have a decent virtual guitar to begin with.

From a satisfied, unsolicited, long-time customer.

(Orange Tree Samples, AmpleSound, and Indiginus guitars all make excellent virtual guitars with more efx features included with the guitars, but as far as playability, for me, MusicLab is still the best)

Dang. Now I have to go there.

Leee
I've been a long time customer of MusicLab's guitars (RealGuitar (acoustic), RealStrat, RealLPC, RealRick) and out of all the virtual VSTi guitars I own, MusicLab creates the best sounding and best performing guitars, IMHO.
First there is the playability.  RealGuitars have the best chord variations when playing chords on a MIDI keyboard.  They offer a consistently dependable chord sound, while other companies guitars often don't play what you want unless you hit the keys exactly the right way.  MusicLab's chord play is the most forgiving, as far as timing, keys pressed, and strumming.  They are also one of the only companies that allow you to play the chords with your right hand and strum with your left.  Many companies only offer it the other way around.  And for me, it's easier to play chords with my right hand.

On to Version 5.  -   I admit the last couple of version updates were kind of "meh".  Offering not very exciting features to their updates.  But Version 5, especially if you own a previous version, for $63, it's a no-brainer.
The amount of new features (including the RealGuitar Steel String guitar, which is virtually a whole new separate guitar) is very exciting. I particularly like the "Voice Leading" feature, which allows you to play a few single notes in between chords, giving chord changes a smoother and more realistic transition effect. 

A few other new features offers reverb, better editing on velocity, Dynamic Velocity Strum, Sliding, and a whole bunch of new types of guitars including 7 and 12 string guitars.  There are a lot more new features that I haven't mentioned, and am still in the process of trying out.

All the new features, things that REALLY add useful functions to the previous versions, along with the already existing preset chord options and dependable playability, make version 5 one of the best updates MusicLab has ever offered.   As I mentioned I have about a dozen other brands of VSTi Guitars, but MusicLab's RealGuitars have always been my go-to guitars, now more than ever.  Many other virtual guitars offer more efx with their products (that is a plus) but since I own AmpliTube, Guitar Rig and TH3, it's not a big deal, especially since all the efx and amp sims don't matter if you don't have a decent virtual guitar to begin with.

From a satisfied, unsolicited, long-time customer.

(Orange Tree Samples, AmpleSound, and Indiginus guitars all make excellent virtual guitars with more efx features included with the guitars, but as far as playability, for me, MusicLab is still the best)

Hey Leee . . . a nice review of Real Guitar 5, I picked it up very quickly after I got their email promo, and am really liking the new additions. It has evolved into a very deep software, and I find if one takes the time to learn it, it can be rewarding.
 
I agree that it has the greatest "playability" factor of the other major guitar sample emulators on the market, though I must give kudos to Indiginus and Orange Tree Samples for their creative approach to a guitar strum interface that is also very user friendly . . . but somehow in the results, just a bit clumsier that Music Lab's approach.
 
My only knock for Music Lab is the "Song Mode" they introduced last version . . . such a powerful idea for guitar based songwriters, but . . . if they could only take it a few steps further for usage in a DAW (like Sonar) ? . . . guess that keeps us buying their updates.

My only knock for Music Lab is the "Song Mode" they introduced last version . . . such a powerful idea for guitar based songwriters, but . . . if they could only take it a few steps further for usage in a DAW (like Sonar) ? . . . guess that keeps us buying their updates.

Yeah, I agree.  I rarely use the song mode, it's just easier to create the song (and guitar parts) in Sonar.
They could also have some better strum patterns, but again I usually just create my own strumming.

I've been a MusicLab Real Guitar user since version 1.5 and I was hooked upon first use.