I agree, I bought the same spec MBP as OP yesterday, for more money… I don’t have buyers remorse. It’s a great machine - perfectly fits my needs, on top the Liquid Retina display looks amazing. It’s really fast. I guess I can use it at least the next 3 years without any problems.
OP don’t overthink it - there is always something new coming out but as long as your Maschine is working good (and it’s a computer to work with not for gaming and having the best of the best graphics) than it’s totally fine!
I like the current model of the Apple mouse tbh, it’s great the scrolling and gestures it’s just perfect for the MacBook.