The POD Pro is basically the same amp modeling technology and effects contained in the POD unit but contained in a rackmount unit with actual knobs so editing presets on the fly is much easier. It has the capability to be controlled by a floor footswitch, though I never forked out the money for it and I don't play out so I don't require that kind of control.

On the rear of the unit it has stereo outputs to go to power amp, footswitch jack, effects loop input and output, and a single guitar input on the front.

Its pretty sharp looking, sitting in a rack all lit up.

Editing the presets is super easy, its as simple as twirling knobs to dial in the desired amp model, gain, eq, and effects. Fine tuning the paremeters on some of the effects would probably require the foot controller but the stock settings aren't bad and satisfied me. I actually did read the manual which is unusual for me, it was very informative and saved me some time tinkering with it.

I played a couple of humbucker equipped Les Paul style guitars through it, while running it into a samson 120 watt power amp, then into a crate 2x12 combo amp I turned into a speaker cab.

The amp models are the typical Line 6 stuff, sometimes you are suprised at how close they get capturing the "essence" of a particular tube amps sound like the Dual and Triple Rectifier models, but since modeling technology is not quite capable of emulating the dynamics and behaviour of tube amps- some models don't stand up to the amps they seek to imitate at all. I LIKED the sound of the "blackface" model but it doesn't actually sound like a Fender.
If you are into heavy riffing, you will LOVE the "Insane" model. Think of a Boss metal zone morphed with a typical Marshall hi gain sound, and there you go.

The effects are quite good, not as good as the Flextone III I had owned previous but the POD Pro was of an older generation so it shows Line 6 is contantly improving their products. Playing in true stereo makes a real difference here though, the effects don't come alive nearly as much otherwise.

The Line 6 DL4 is delay pedal with 16 different settings, all based on other delay pedals. It also has a 14 second loop sampler. There are 1/4'' mono and stereo inputs and outputs and has 3 spaces for making your own presets and also has a tempo tap feature.

The pedal is very easy to use, although it takes some time to master it and to reach its full potential. Each knob has a different use for each setting and I would recommend looking at the manual for the full information on that, just because there is so much information and so much you can do with the pedal. Overall, its really easy to get some great sounds out of this though.

The effects on this are impeccable. While some are better than others, all of the sounds are very realistic and they don't sound too 'digital' at all. I use this mostly on electric guitar but I have used it on keyboards as well, and it works great with both. My favorite settings are the sweep delay and the reverse delay. I used the looper constantly, most of the time I just lay a chord progression down and make up lead parts over it - its a really great writing tool as well.