Both boats are built very well, but they will be hard to compare in all honesty, they are very very different. The 265 is a big boat for its size, but measures 25'9" from transom to tip of the bow...not including pulpit, the stamas is much bigger. The stamas will be more boat, but much of that is in the cabin, the cockpits are similar in size, but the Grady does not have the euro transom, which for fishing can be a pain...personally I hate them and will never buy a eurotransom boat, I will go diesels when I jump up in size, or IPS powered. Both boat brands have great customer service and use great qualitty materials to build there boats. The beam on boat boats are about the same. The helm is a huge difference, the Grady has a lot more room to get your crew or family out of the elements as well as comfortable while running around, it is also nice to have everyone together when making long runs instead of people spread throughout the boat, too far away to converse without yelling. The Grady holds more fuel, if you run offshore that might be something to consider, if you stay close to shore it matters less. As far as weight, they are close enough so that will have little effect on the decision, fuel burn should be similar for both, although the stamas being longer at the waterline does help it a little. The cabin on the stamas does offer a smaller under deck berth which is nice, but typically is only used for storage or for smaller kids. The v berth on the 265 is longer and less cramped for adults. The table in the stamas is nice, but from my experience is probably the least used feature in a cabin this size.
As far as ride, Stamas's typically have less deadrise aft, I have been on a few 27 and 29 tarpons, and my 265 had a better ride, the Stamas was solid, but had more hull slap from waves and had a different feel when hitting waves. This is not to say it did not ride well, but I personally perfer the 265 ride more. After staing this, the 265 being shorter and wide, will make it rock a little more on the drift, but only a slight bit.
As far as ride, you need to test both on the water and get a feel for both, neither boat uis a bad boat, they just offer 2 different things. The Stamas has 2 ft aft that personally I find to be wasted space, having fish boxes and a large well is a nightmare for hardcore fishermen, especially if you fish for bigger fighting fish or pelagics. If you anchor when fishing, the eurotransom poses a big issue, if you troll more you will be boating a fish along the side anyways and it matters less. Getting on a 265 is a little tougher then on the stamas with the eurotransom, but with a swim platform the 265 is not bad getting on. Think about the helm, how many guys do you go out with, do you want them protected from the elements and comfortable, or spread out, in bad weather do you want a cramped helm with guys standing or seats for all. Think aboyut the view from the center helm vs a stbd side helm, the center helm is a dream, line of sight makes manuveuring a dream, and makes the boat feel smaller when running and docking, much easier to manage. Do you need more cabin space or staorage, if so the stamas might suit this need better. The stamas does have a walk around which makes passage to the bow easier, but if you rarely use it then your just losing cabin space inside for no real gain. the 265 is not difficult going forward, but not as easy as a true walkaround.
My advice.....sit on both boats, in the same day if possible, and make a list of likes and dislikes and see which list suits your needs better, then take that one for a sea trial, if the ride is what you want, then your decision should be easy. If your still stuck between both, sea trial both if possible. As a side note, as Tim said, a ahrdtop is a big factor also, a hrdtop on a boat this size should be standard, not having one means a big upgrade if you add one and a bit invested down the road. I could not imagine owning a boat this size and not having one, you will lose electronics boxes which on a boat this size you will need to have a full array of electronics. A bimini in this size boat is somewhat silly to have, you lose the ability to have rod storage off it, a t bag for life jackets and such, a place to mount your electronics antennas out of the way, as well as as high as possible to utilize their full potential, and a hardtop is a big big benefit to resale value down the road.
