In response to your questions, socko:
1) Yes, it is for sure. However, personally I've found it to be a "noisy" psychedelic, in that it provides you with so much visual and aural stimulation that it makes it difficult to concentrate. It also contains quite a bit of mind fuck at 3.5-4mg, which is also where it starts to get profound. The result is that I've not yet determined how to really let myself go during the experience after about 5 or 6 trips with it. I've often ended up getting stuck in a loop of doing the same things over and over again, stuck on the same minute of the clock for seemingly the majority of the peak. But DOC is really, really powerful, and I think it allows you to connect with your subconscious/unconscious mind very easily if you can work out how, which is the same as the universal consciousness. it doesn't seem to deal with personal issues much like I find the 2Cs to do. At least this has been my experience.
2) Yes, the state is quite fun to explore. it's shockingly intense, while remaining pretty emotionally steady and non-scary. I've had great trips that ended up being primarily recreational, just because the body high feels pretty good, not too stimulating (though definitely stimulating), and the visual effects are tremendous. Also keep in mind that, for me, it took until the 4th trial to really fully be able to enter the state. That trial was with 4mg and was the first really hard trip I had on it. From then on, each new trip has picked up where the last one left off, and it's gotten more and more intense and serious and deep each time. Also, it only takes me 3mg now to get to at least the same level that the 4mg trip got me to.
3) Definitely, absolutely not at 4 or 5 hours! it builds pretty quickly, and I'm usually starting to peak by 2 hours or just after, but the peak reaches a peak at about 5-6 hours at which point I'm fairly incapacitated, and frankly unable to be bored, due to the intense psychedelic stimulation and mindfuck. After about 8 hours I can sometimes fall into a sleeplike trance which definitely isn't full sleep (as I usually take it at around 11 at night), and then the whole next day I'm lightly tripping. I go back down to a +2 at about T+8 to 10, and ride that out until about T+16, and then I'll be at a +1 again until I actually sleep, no matter how long that is (it's been up to T+30 after ingestion). I personally really, really enjoy this day after light trip though, although some people find it annoying. Once I reach a +2 I could go out and do stuff, but there's a fair amount of pupil dilation and paranoia when in public. During the day, the visuals from DOC while outside are miraculous and truly beautiful beyond words. I've driven at T+10 before but I don't recommend it, although I ended up driving for about 3 hours into the mountains.
DOC is one of my all-time favorite psychedelics, but in my opinion it's difficult to use constructively, and in fact I've not yet figured out exactly how to do so. Although I have made progress. You can search for my posted experiences in Trip Reports if you want, as I think they illustrate the experience that I have on it pretty well.