They are usable depending on your expectations.
I played with an EXP only in a band that was not ~terribly~ solo-heavy. So I needed a wah for funky rhythm parts and the like, and it was totally fine. The whamme doesnt track as well as Digi’s, but it was usable if it isnt the total focus of your lines.
NOW, I play more solo-heavy stuff, and I have an Xotic Wah on my board. I don’t use the Whammy enough to want one though. When I need it, the H9 suffices.
You should, however, get a EXP for the H9 for OTHER reasons. It’s use on fading in delays, sweeping effext mixes, etc is totally worth a spot- I think moreso than a DigiWhammy on anyone’s board except Tom Morellos 🙂 Then you can test out the Algos for yourself, see what you wanna do.