it's hard because they work in different worlds.
Tommy works on really old stuff, uses old methods, which is fine, if that is what you want. Things like he go to great strides to manage water on the outside of the building using good layers/techniques.
Holmes also does good stuff and also focus on the shell of the house. He tends to solve things via modern products, which again can be ok. I think there is also the issue that we see Holmes working with vendors to offset cost for the show. Where TOH is more of an advert for over the top appliances and products for their sponsors. No real idea what each would use on their own.
Since we tend to see one do repairs and the other do rebuilds, it's hard to compare how they would do both new. I think ideal would be in the middle someplace.
Big thing would be who is designing the house? I wouldn't let Holmes make any style/design choices. He also tends to like things that others would not (vinyl windows). His sense of design/style tends to be bad, which later shows look like he finally addressed and now uses designers.
If you are building a modern high efficiency type home, (say concrete construction), go with Holmes. If you want say a more classic style home, maybe a timber frame, etc. Go with Tommy.
Both do good work, both have short comings. Also which country are you building in. It would be interesting to see them work on a house together, or "compete". Maybe have Mike build the structure, Tommy do the finish work.