I would say the opposite vs the KoKo boost. The mid side of the KoKo can gain up pretty nice but the OD side of this pedal will get more gain if you crank the knob. On a stock JCM800, my gain knob on Mike's pedal does not go past 1 o'clock really. The boost side of Tube Plus OD is not as thick/bloated (one of the things i don't like about the koko) and more transparent to my ears. It makes it the perfect pedal for a JCM800 or any other good crunch you want gained up or just a tad more hair on the top for 70's rockin. The advantage of the Tube Plus OD is that with the gain up, it stays tighter to my ears than the KoKo. Both fantastic pedals though. I followed up with Mike a while back and he asked me if his pedal had replaced the KoKo on my board yet. I said I loved his pedal but no, they both had a place and they would both be staying. This is how I have used them:
With my 800, when the master volume is lower and you can't crank it, the Tube OD is killer and perfect for getting all levels of gain.
When I open up the Marshall to 6 or 7 on the master for recording, I need way less gain. More people should experiment with this. In those situations, I will use the KoKo mid side to just give me a push and I can play leads with that amount of gain no problem. I like to work for the notes a little more though. Makes your playing more authentic. The mids on the KoKo also offset the Marshall thickness at high volumes. KoKo (mid side) + 800 + hot enough pup = Matthias Jabs tone!