do any of you dj with just the 404?

you'll have a bit of trouble.. if you had 2 you could do something maybe..

it's lack of a normal pitch function will make it hard to match the speeds tho unless you pre-pitch everything to the same BPM beforehand

also you will have trouble with only being able to control 1 thing at a time - eg only change the volume of 1 track at a time, only being able to apply eq to one track at a time.. 2 404's would be kinda cool

Well DJ is a big word, but I think quite a few things are possible when you do proper pre-mixing and make sure different BPMs don't mess up the flow. You don't have to match BPMs if you use sample stabs to make a transition or for example the DJ FX looper.

I have already used the SP-404 to play around 6 house / trance songs in a row successfully. Some of those songs had fade-outs, but not all of 'em.

I totally agree in that it would be easier to have more SPs so you can keep at least one of them outputting audio continuously while preparing the other for the next transition.

Use a (DJ or normal) mixer in between and you've got a pretty sick way of doing a live show for not a lot of money.

Two 1 gig cards, two SP404s, you'll be able to do a serious gig for sure!! In fact to some extent that's ("going to be", as I need to buy some more cables atm) the SP-404's purpose in my case, but I use it together with an MV8800 instead of another SP.