A 1-4X scope is probably the best all around scope for up close and fast shooting and good accuracy out to 300 yards or so. For all around use I'd much rather go this along with BUIS. I've found it to be just as fast as a dot sight up close, and far better at extended range.
For a dedicated varmit rifle the 3-9X is really a better choice. The higher magnification will help with precision shots on smaller varmits at exended ranges much better than a 1- 4X. The bigger objective helps a bit in low light too.
A good 2-7X might be a good compromise for you. 2X is still pretty useable up close and 7X on the high end will be better than 4X.