I don't know anything about them.
Just understand that the 700 action was designed to be cheap to produce. The Blaser rifle was designed to be an extremely accurate switch caliber system with a very fast straight pull action. So they are quite a bit different in design goals.
The 700 advantage is that parts are very widely available and any competent gunsmith can make you a barrel. With Blaser you need to use their barrels and never requires a gunsmith. However I think Blaser barrels are at least as good, if not better, than custom barrels I've used. They are accurate and the steel is very good so they have excellent barrel life.
If you like tinkering with rifles, the 700 is a better choice. If you just want something accurate and reliable and are OK with not being able to customize/tinker then the Blaser is a better choice. In fact, I recommend you never take a Blaser into a gunsmith to do any kind of work unless they are Blaser affiliated. They can only create misery for you. But with that said, my Blaser has fired a lot of rounds and my mate's have fired countless thousands of rounds as well, and we've all never had any issues with them. They just work, are accurate, and always return to zero.