In my experience DXM is a fairly unenjoyable drug, it is made more bearable with the addition of marijuana. The first time I did it I took the dose in halves and before the second half it was like a real fun sort of energetic high. Me and my mate who also took it were walking around the streets walking like idiots in all sorts of manners doing somersaults and rolling around pretending we were ninjas and shit. You take more and its a bit harder to move, you get a weird headspace but not really on the same level as tripping on shrooms or LSD and theres some distortions but no real open eye visuals.
I find the nausea and the Robo itch to be quite unpleasant, especially the itch, that feeling is undescribably annoying, twice was enough for me with this drug. The only way I will ever use it again is my little brother and a friend or two have expressed a degree of interest in it, should any of them ever try it I would consider taking it with them for their first experience and even then, the only person I would definately take it with is my brother.
Marijuana brings out some of the more positive effects while reducing nausea I think. I believe anyone interested should give it a try so long as you have done a little research and know what brand to buy (Robitussin DX for those who don't know) considering its cheap, easily obtainable and fairly safe to use a handful of times assuming your not stupid, in the end I feel the majority of people will not want to repeat the experience after 1-5 times as has been my experience and that of everyone I know who has used it.