My first scope was a 4.25" reflector. After two years I upgraded to an 8" reflector, and it was like having a whole new sky! The difference was unbelievable.
You'll find a similar difference going from the 130mm to the 8", but the 10" will be even better. I personally find a 10" f/5 Newtonian to be close to the perfect size: large enough to give fine views of deep sky objects and the planets, yet still portable and suitable for sit-down observing.
I'd also recommend going for the IntelliScope version, even if you don't buy the object locator right away. The intelliScope version has better bearings and the very useful altitude tension adjustment.