I like the Digitech Trio Plus as my 'looper'. You set the chordal structure, tempo and length of the loop first and the Digitech Trio Plus creates a drum and bass section depending on the genre you set. The bass part will pick up on the chords you played and build a bass part. You can pick different types too within each genre if you don't quite like the first option, change the bass complexity and the volume of both. As you also set the length of the loop, once you are happy with the bass and drum beat, you can start building the Rhythm guitar. Its really easy too as you don't have to hit the record and stop recording either. It can start recording as soon as you start playing and will stop recording at the right time you set up at the start.
You can build songs too rather than just a repeating loop. It has the ability to have 5 different parts - like a verse, bridge, chorus, solo etc section so you can build up a song with different chords, style/beats etc and rhythm section too Then just programme in the song structure - ie verse then chorus, back to verse then chorus followed by a bridge into a Solo section back to chorus, verse, bridge 2, chorus, chorus, end. Its a bit less tedious than playing over the same 12 bar loop over and over again. Of course if you just want to practice soloing in different modes, different places on the neck, different scales etc over the same basic 12bar loop, you can do that too.
What I like about the Digitech though is that it uses your input to build a bass/drum beat that you can change until you find the one you want to build upon. Not being a metronomic click and a lot more interesting than picking just a drum beat from a small choice to practice timing to. The simplicity of the Digitech also means you aren't messing around trying to get the 'start/stop' timing right if you want to build a loop and it can be as simple or as complex a song structure you want. Its easier than trying to find a drummer and a bassist, maybe even a Rhythm guitarist if you want to practice lead guitar.
Each to their own of course, I prefer the Digitech Trio Plus as looper and backing band in one device. You of course are the Rhythm guitar in the loop and lead guitar over the top to practice different scales and modes, not just on one area but different places up and down the neck if you want, try different licks and create your own solo's.
Another option I have at my disposal is the Boss JS-10 which has backing tracks as well as the GT100 suite of guitar effects. You can use the Aux port to play your own music, slow it down to if you are trying to learn a solo. Its a decent little table top amp and effects too for just practising and noodling at home with. Certainly better than just practising scales, modes etc with no backing track, rhythm section and just the click of a metronome. I think the JS-10 is a decent bedroom/practising tool. Even if you are a gigging/touring musician, you can use this as a warm-up amp, bus amp, hotel amp etc - have your entire set list plugged into it and practice your solo's etc too. Its a great tool for musicians regardless of skill level - from beginner to pro!
