Both are excellent in their own right, depending on your priorities and preferences. I see you like the Lord’s reticle in MSR2 so congratulations are in order….
If you go with the S&B make sure to get the DT2+ turrets as they are by FAR the best option. Glass in Schmidt scopes is always very good so it’s a great option even if the design is older. I hear the new 6-36 is even better optically.
The M7 can be a very nice option but can have a wide variance in optical performance in my experience. I have several and a couple of them look excellent and a couple are not as good. Not worth paying full price for new but if purchased used for the price you mention, it will not restrict your shooting in the least.
I’ve had or currently own every scope considered mid tier and alpha class. I can honestly report NONE of them made me a better shooter, but some are more enjoyable to use than others.
I love the Tangent Theta and it is great in every way, except I wish they would put in the MSR2 reticle. No matter what, it seems to be a compromise at some juncture so I just pick my favorite features and go from there.