I have both, each does what they need to do perfectly.
The TC just takes time to setup but if you use a PC you can literally make it the best noise gate/clamp/suppressor ever because you can do frequent specific adjustments and the ISP can’t do anything remotely close to that.
BUT for the ISP to even compare/compete you have to use two. That’s the real drawback to the ISP. The best part about the dual ISP setup, does all the work for you with 2 knobs.
These are my thoughts. I love them both, but the isp is way more expensive and complicated because it requires two pedals with a link cable to complete with the TC’s full capability. TC is way more involved and requires a PC for the good stuff.
I love the TC and it’s fricken awesome, great choice for a gate. Sorry mines not for sale, and I hope you find one.