I've owned a Cobalt Flux for 4 years now. It works perfectly but it isnt arcade accurate by really any means.
The pad is completely flat, and from the beginning this caused me to lose place very easily since back then I was a very avid arcade player. I literally would sometimes fall off the pad while playing, thats how disorienting the flatness is. I don't have the arcade mods, but I did remove the plexiglass and decals from the arrows to give it some depth, and I've had no problem orienting myself since then, even if it does mean the pad looks ugly.
The biggest problem with the pad is the "feel" of it. As a buddy told me, it has a "squishy" feel to it. When you hit an arcade pad, it feels very hard and feels like a hard stomp. When you hit a cobalt flux, it feels like you squish the pad. This presents absolutely no timing issues what so ever, but it definitely doesn't feel like an arcade pad.
These problems set aside, the Cobalt Flux is a beast of a pad. Its lasted 4 years and its still running like it did when I first got that huge box. Just remember what exactly you're buying, a strong and durable dance pad, not an arcade replica.
Konami should really release more of those ASC's they had yeeaarrss ago...those looked gorgeous...
Anyway...as for bluesharks:
YouTube - blueshark pad overview
That same buddy I mentioned has two of those, and judging from this video he made showing off the pads, they seem to be more arcade like than the cobalt flux. I especially love the fact that the inside of the panels actually look like the inside of an arcade panel. I have never actually played on a blueshark but I would make a bet these are better than Cobalt Fluxes. Unfortunately, they cost 100 dollars more than a Cobalt Flux...the bar also looks really flimsy (
MySpace Videos: Delirium - A by -{InPhinitY}- MinDphazZeR) =/
Im gonna see how I can get my hand on one of these...the panels look super promising, and since I don't bar rape, the bar sucking really doesn't matter to me.