The way it is set up now, I can use it for basic loops involving static chord progressions when playing solo acoustic guitar. It is easy to get in and out of the loop, and Line6 thankfully included the 'play once' button, so on the last repetition of the chord progression, you don't have to be too picky about when you press the button to end the loop. They carried this idea from the DL4 and M series, which works really well.

What they didn't carry over from the older pedals is the ability to control the volume level of the loop with the exp pedal. Abrupt endings to very dense loops (which the HD is very capable of) is a pretty jarring sound to an audience. It would make more sense to fade out the loop while playing live on top of it. So if you are the type of loopist who uses the loops for textures or improvisations, the current revision (1.43) of the firmware makes the HD crippled in the loop department.

I personally use it quite a bit live with my acoustic duo which is just me on guitar and vocalist so I'm able to use loops to back up certain things and make it more interesting.

We do cover of Foo Fighters "Best Of You" and I will record the first time round the chorus on the fly and then play the octave harmony parts over the loop.

For a cover of Evanescences "My Immortal" I record a loop of the first time round the chords for the chorus, which also happen to be the same chords for accompanying the solo and this allows me to play the solo with myself. Haha.

For some songs I will record a loop and then switch to a bass guitar sound on my Variax Acoustic to play over the chords and then fade out gradually for outros! (It's fun watching people get very confused at that!!)