Ralphie, the oak we had milled was beautiful stuff, but it was hard. The pine was easy to cut except for the jack pine which is quite hard. We did not cut any tamarack, but I can tell you that it is an extremely hard wood when dried.
The oak was hard but it cut easier. I think it was a two fold problem. The pine seemed to have sand embedded in it and the pitch was a problem in gumming up the blade even using the soap lubricant.
The changing of blades is a big deal to me at 20 bucks a blade also.
Piece by piece the pine might cut faster but when I figured in blade changing and cleaning the oak went better. Yea, my oak is extremely hard too, I have to shoot the nails through it. A hammer is worthless...almost.