i can't say if it's like iv coke really. i've only ever shot cheap coke and didn't really get much from it. but the first shot does feel pretty fucking good.
i have however IV'd quite a bit of ethylphenidate, i wouldn't recommending IM'ing it. as said, it feels harsh on the veins and nose, so i don't like the idea of it sitting around in your muscles. the first shot is great, nice rush, really euphoric, the high lasts around 30 min, with residual stimulation for a few hours. on redosing (which is really compulsive), the rush, high, euphoria etc diminishes quite rapidly, but of course is still very compulsive. i don't plan on getting anymore for a while because when i have some i just shoot it til it's all gone no matter what i'm doing/ have to do. check
this thread i wrote.
i once did a "speedball", of ethylphenidate and heroin, and the ethylphenidate completely overruled the heroin, and as it has a long residual stim, it was as if i didn't put any heroin in there.
if you decide to iv ethylphenidate, measure it with scales (start low), be careful, have someone around, make sure you have some benzo's in case you need them and only have a small amount available, because you will probably shoot it until the bag is empty.
hope this helps