I think the overall midrange and trebble character of the two amps (23.5 and 27.5) are similar. The 23.5 has more bass impact and seems to go deeper into the depths of the lower registers. I am not really familiar with the 300 series sound, but I can say that I am quite happy with the sound of both the 27.5 and 23.5. These both can be bought for quite a bit less than a 300 series. II don't think you would be disappointed with either the 23.5 or the 27.5. Only you can decide if it is worth spending the extra money for a 300 series amp.
How much power do you need?
Good luck with your search and happy listening.
How much power do you need?
Good luck with your search and happy listening.