The wiim pro has a remote control to adjust the volume, advance the pause morcaux, etc. and you can also adjust the volume from your phone using the Wiim app. I would not recommend this as the sensitivity of the phone is not as precise as that of the wiim.
Sincerely
Pierre

Well, following the answers below, I bought the wiim pro and its remote control. But still can't play my itunes playlists (music app) from my iphone on my amp. The wiim app doesn't display my iphone playlist content (like Cynch does for example). And in the Apple music app, there's no indication that I can stream via the wiim box (no cast icon). It's not complicated though, I just want to stream my playlists to my amp ... Does anyone have a solution?

Works for me without any problems. Both with the wim app and directly from itunes/music via wifi.