The 2500 is the same size spoolas the 3000, the 3000 is just cut deeper for the line capacity in the Shimano lineup anyway, my concern would be balancing the outfit, and weight wise there is no difference. On most 7' M rods it will require at least this size reel to balance it, my MHXF 7' with the 4000 size reel balanced great. If this different and there is an oz or more difference, see what balances best would be advice.
If one of those two are your preference and balance isn't an issue, you just need to decide how much line capacity you want. I use the 3000 on Lake Erie and big reservoirs because I like to pay out 100 yards or so to drift riggs on the bottom for Walleye, sometimes you get big cats, drum, or other large fish and the capacity gives you enough to play the fish instead of pulling all lines in to chase them before you get spooled. Usually you can tire the fish enough to start gaining on him before this happens. But for most Bass fishing and cast and retrieve applications the 3000 is a waste of line. Just the way I use em,,,,,,,