I personally have used a Leupold Vari III 2.5X8 for about 20 years on my 2 Model 700 7mm mags, 300 win mag, and 270. When I purchased all these scopes the 50mm objective was not available yet. That is the only thing I would change on each of these scopes, for the light gathering power.
The 4.5x14 is mainly a varmint scope used for long distant shooting, out past 300 yards on smaller targets where you really have to dial the target in.
I think the 3x9 is probably the most popular high power rifle scope for any manufacturer.