I purchased a 27 spare spool for my 25 but when the performance was so much better, I sold the 25 spool. The 27 casts noticeably further and as mentioned earlier, having extra line is never a bad thing. The 27 spool also creates a slightly faster line retrieval. I use it on a setup with low riders(gsb1321M) and it casts almost as well as my emblem. Never once had a problem with line getting under the roller during a cast(had it happen many times with a 706 or converted 704 though

).
I know it wasn't the question, but I would definitely go 27 on that setup.