i know their are obvious advantages of the 404 over the 303 but is their any point of having both.

Sure!
303 can resample the ext source 404 cant
303 has the nicer vinyl sim (in my opinion)
303 looks sexier (in my opinion)
303 has the better mark function (sample doesnt start new when trimming start or end, you can even reverse the sample while marking on the 303 which is dope if you got long loops and only need to trim the end a bit and its much nicher than on the 404 (in my opinion))
303 has better pads (in my opinion)

Hope that helps a bit

edited for HELLOPILLOW

YOU JUST FORGOT TO TYPE "IN MY OPINION" BEFORE BECAUSE FOR ME :
404 IS FASTER
404 OG HAS A NICER VINYL SIM
404 PADS ARE HARD BUT THAT GATE IS TERRIBLE
404 HAS MORE MEMORY
404 RUNS ON BATTERIES
I STILL PREFERE THE OG RATHER THE SX (NOW EVERYONE SUCKS THE SX EXTREMELY CLEAN SOUND :S )

edited my post Sure there are lots of PROS for the 404 that's why i love that one too!

404OG > 404SX in my opinion. SX lacks the Vinyl sim compression but got a very cool flutter in my opinion.

i started on 404sx then copped a 303 and fell in love and haven't stopped making 303 pattern sequence beats but a serious disadvantage is the memory limitation, one time with one of my intricate 303 beats i've used the 404 to bounce sections of the song to while i work it piece by piece then put them all together on the 404,
also the 404 has a ton of fx a 303 doesn't that are awesome and the ones it does have in common are all different sounding, i'm not gonna disclose some of my secret double sp techniques but i'ma just say that using them both simultaneously is fucking amazing and i haven't stopped using them both since i copped the 303

also the sx is a great interface to put music on the computer because of the sd card storage

its a good idea to keep both and imo keep it u got 2 relics homie.

404 use as main to make all your shit then record straight 2 303 because the 303 is nice enough to resample + record ext source (so it beats the polyphony limit u deal with if u wanna record stereo or multiple pads at once). having multiple sp's is good anyways to shoot ur tracks back and forth and each have their own unique type of sound, why not have both? i own a 303 404sx and 555 and its great to have options when u wanna create.

Also 303 can resample while a record is playing via EXT. Source.

I have both and wouldn't give up either, all my SP beats are 99/100 times made on the 303 for the sound and workflow which are better than the 404 in my opinion.

But I wouldn't sell the 404 as its a dope tool for live shows and play all of my sets exclusively on it, the memory capacity is so much more than any of my other samplers, you can use batteries in case of emergencies and the efx keep loops interesting.