Boss does not really have any other delays with a tonecontrol.
Why is a tonecontrol great on a delay? Try the delay setting on the RV-2 and you will find out!
I know some people do not like the delay function on the RV-2, think it is too short and useless, however the delayfunction is great for short delaytimes, and because of its tonecontrol unique in sound.
There are not many delays around which do have a tonecontrol, I do not know why.
why would you want a tone control on a delay anyway?
To change to character of the delay, to select between crystal clear digital repeats and murkier sounding analog type delays. Helps things sit in the mix better.