As for controllers you get Korgs one true genius innovation, the Joystick. It is so much fun and so much better than the seperate pitch and mod wheels. The cool thing is you can assign it to do different things like tweak filters or at vibrato. You also get an expression input, and sustain input.
As for connections it has three audio output options, stereo, aux 1, or aux 2. I say "or" because as far as I have figured out, you can only use one or the other, no combinations (bummer!!). It also has midi in/out/thru (nice) usb (for some reason it doesn't work well with my mac, it actually distorts the signal somehow, could be my computer though), SD memory card slot, Sustain pedal input, expression pedal and expression switch (tap tempo, effect on/off).
It has around 80 effects but most of them are the same effect stereo or with slight variations, but it includes reverb, delay, overdrive, ring mod, detune, phase ..... I think about every standard effect. Each effect can be edited and you can apply two per patch so you got some pretty decent options. As far as I can tell you cannot edit anything through a computer. The usb simply lets you play vst programs, at least thats all I could do with it.
This has 128 polyphony, more than you will probably ever need.
The "general" configuration is pretty simple. I was skimming through patches and playing withing a minute of looking at the keyboard and not referring to the manual. To use this things full potential will take some serious manual study, but that is to be expected with this many options. It comes with two fairly thick manuals and they are not to bad to use. Leaps and bounds better than some roland manuals I have had to use. I would say 75% of the time I had an idea of how to use this thing, I could figure out how to do it by reading the manual for ten minutes, the other 25% it simply didn't do what I thought it was capable of (i.e. upgrading patches without buying the sample upgrade). Almost all the sounds and effects can be drastically edited which is great, but I would not say it is easy at the start. You really need to consult the manual on how to travel through all the menus, but again, they are really helpful and clear. Infact, each effect (1-around 80) has a section in the manual explaining every option you can tweak.
This was my first leap into sampled music patches and programs and I would have to say it was a good beginners tool in the aspect of sound quality. I know a lot of Reggae/R&B musicians who love the sounds these make, but for most of the sounds I need better quality. As for realistic, I would say close, but overall no. The Acoustic piano patch is probably the biggest let down. It just really lacks in realism. I have played with all the options and still can't get it to sound even remotely "full." Some of the world music instruments and mallet instruments are pretty cool, but most of those don't sound realistic either. The sounds I do love on this instrument are the pads. A lot of the synths are pretty cool too but the pads are the best by far. You can really get some dramatic ambient layers out of this keyboard. The arpeggiator is pretty sweet to for all the synth sounds, it really adds that "dance" sound to your arsenal. The expressiveness is pretty good. I pretty sure its about even with other keyboards in its range, but I wish the hammer action was a little meatier. It is almost too easy to play sometimes, I have had a lot of opportunity to play really nice grand pianos so I am probably a little biased, but I really have come to appreciate the resistance and hardiness of a real piano keyboard. I am currently on a search to find a really good weighted keyboard that comes closer to the real thing.
I have had this keyboard for three years. It was a great first step into sampled music, but I am ready to ascend that stair case now. The best thing is the amount of sounds you get in this machine, just about everything you need in a studio. The bad thing is that most of the sounds are not "real" enough. I have tried more models after I bought this than I did before, so now I know I should have shopped around a little and spent more money (i.e. Nord Stage 88, yamaha motif). I got mine for half of the original cost, which was a Great! deal, but like I said earlier, I wish I had saved up for a better unit. I am actually trying to sell this one now.