so here's the thing...i have all the DMCs and i've played many hours on NG sigma and i enjoy them both but i must stay from my experience with both:
Devil May Cry has way more interesting and detailed environment design where as NG's comes off way too sterile.
NG's combat system is much more ridged as well with "must hit in sequence in order to get the proper move" combat instead of the more fluid customizable combos that DMC offers.
although neither really have amazing plots, NG's is far cornier than DMC's...at least DMC seems to not take itself too seriously where as NG try to play it off and just ends up falling flat on it's face in comparison.
DMC also offers more variety in weaponry. while DMC may not have as many weapons as NG, it certainly has more variation between the kinds of weapons and how you can use them.
DMC is just funner: more flexible combat, more interesting environments, funner and characters and more interesting enemies.
even the music is more badass in DMC3 and DMC4 than NG...WAY more...definetly get you amped and into the game!
and i must say that, based off the latest DMC4 videos @ gametrailers.com, i can't say i find the cut scenes but be anywhere near as corny as the previous ones and yet they still maintain the enjoyable wit and humor of the series.
oh...and here's this:
http://onaxis.blogspot.com/2007/12/1up-previews-devil-may-cry-4.html
PS3 version is looking better than the 360's...(i just like to throw that in the 360 peoples faces because, around here, the PS3 fans get nothing but continous and unwarranted bull crap from the xbots *cough* Fenrir and WHF *cough* about this sort of thing)
in short: DMC >>>>NG
oh..and people...stop trying to win this "Dante is a manly man" thing...because having a rose in your mouth while battling demons is anything but "super manly" and who the hell is playing these games because the main charaters are macho-men anyways?...i mean really...come on...Dante is kinda metro (though he's, in 4, got some stubble) and Ryu walks around with an impenetrable wedgie and S&M wear...deal people...