The best recommendation that I can offer in order to understand the difference between a LS25MKII and a LS26: demo both pieces of gear in your own environment. Just as soon as I offer one attribute of one piece of equipment over the other, someone will post here that they never experienced that with this particular piece of equipment. And for good reason. All systems depend on synergy. And, in my particular system and room, the LS26 was far superior and worth the additional dollar investment. You may have a totally different experience or your expectations my not be the same as mine.
If you do not have the opportunity to demo, purchase used and sell if you are not pleased with the outcome.