Just looking at the numbers, it seems like more is lost than gained by buying the 2.5-15x. You pickup the 2.5-4.5x magnification range, but you lose the 15-27x magnification range. The size and weight are similar. Unless that 2.5-4.5x range is important to you, I'd suggest that you keep shopping for a good price on the higher power scope. You may pay a little more on the front end, but more than likely you will end up with a more versatile scope in the long run. Wish you the best.