I have both.
Each has tools that the other one doesn't. If you need a tool that only one of them has, then obviously that's your answer. But if all you need is the basics, like pliers, knife, or bit driver, either would be fine. The MUT is bigger and more robust, but the TTI is lighter and more compact.
I recently had a need at work for something like a hammer, something to pound something with. My TTI was my normal EDC at the time, and I had nothing else suitable. After that day I decided to switch to the MUT, since it does have a pounding surface. But I've found it to be bulky and heavy to carry, and I'm probably going to switch back to the TTI on my belt but move the MUT to a bag I normally bring to work with me.