Here is a link to a '26 review. It is on a site maintained by Chiles, a former '26 owner and member of this board.
http://ccridlin.home.mindspring.com/
The model reviewed is an earlier I/O FBSF but the information about the construction etc. should all be the same. It is the exact same hull, deck etc.
The Napier desigend '26 seems to me to be a kind of "Value engineered" version of the Hunt 25. Things that you will see which are diferent include:
The aforementioned V which does not round out at the point near the transom in the 26 as it does in the 25. I am not sure why they did this. Maybe to avoid copyright controversy. The effect is the 26 may be harder to keep on a plane at lower speeds. My 26 FBSF has trim tabs and newer lighter engines and planes nicely right down to 17 knots, tabs neuttral. YMMV (That stands for "your mileage may vary")
There is no bump out at the transom in the 26. The transom is flat.
There is no tumblehome to the topsides aft
These two changes made it possible to mold the '26 hull in a one piece mold vs. the 25 two piece.
LOA, Beam, Displacement, deadrise, .... all darn near identical. The 25 is 25' plus a couple of inches. The '26 is 26 feet minus a couple of inches. Beam on both is a fraction of an inch under 10 feet making them right at or just barely over the maximum beam to tow without wide load permits. Most owners don't tow very far very often, and don't bother with the permits. It would have to be a pretty astute and nict-picky officer to site you for it.
The 26 has a raised curb on the deck that gives a tich more headroom in the forward cuddy, but several inches in the main salon of the hardtop and fly bridge models. ( Lack of headrom is a common complaint about the 25 in these versions.)
The 26 has BIG hatces that can be removed to change tanks. Until a couple of years ago no one gave a hoot. But a fuel tank change in the 26 is pretty easy.
In the hard top and fb models the deck house is a little longer making the salon feel a lot bigger.
The '26 was made in Aus up until a year or so ago and there the FB and deck house design mirrored the old HUnt look. In the USA the Napier design of these elements is less curvey, more angular.
http://simplifying.net/phpbb/viewtopic.php?t=1102
SInce a lot of these changes only have to do with the deck house and salon accomodations they won't matter to you, but since you asked....
As far as performance and durability goes the '26 is just as rugged a ride as the 25. It seems to perform pretty close to the 25 as well. I honestly think it was Bertram's intention to pretty much design a 25 that was faster and easier to manufacture. (Read the article about the modular design of the deck, hull and house.) Also look for the thread here recently here about changing the tank out.
The 26 was made in I/O versions with the stright 6's. In that case a repower with new 3.0L is relatively easy and a good fit. They also were produced with inboards. Later the 26 was the onnly Bertram ever offered from the factory with outboards as an option.
Peter