I've been extremely interested in the Fillmore series since they've launched, especially as a do-it-all amp to help me minimize my rig. As I've looked and listened to the 25 and 50 watt combos, it seems to me that aside from the smaller size and lower weight, the 25 feels somewhat superfluous. The 50 is switchable down to 25 watts, the cabinet is a bit wider which would seem to help fix the boxy sound the little bitty Mesa combos seem to have, and clearly has more headroom and ability to keep up with a louder band if need be. Obviously, a switchable 25 watt mode is not the same as an amp designed for 25 watts, but does allow one an extra option to tailor the way they want to interact with the poweramp. But, for only $100 more, it seems to me that unless you really need to save space and the extra 10 pounds to carry, the 50 is somewhat of a no-brainer. Or I suppose if you just love 6v6s in the 25 over the 6L6s of the 50?