Yes, living 255 years would be fantastic. Just 60 years ago, most humans didn't know what a computer was. If you consider 250 years ago, the United States of America had not even been established. The limits of human technology and advancement are continuing to be pushed, and at an exponential rate. It is impossible to predict where the world will be in this amount of time, but one thing is for certain: the developments of human society, technology, culture, and scientific understanding, will be outstanding and surely able to amaze any individual lucky enough to live for 2 and a half centuries.
If my health and body started to deteriorate as I reached my 60s or 70s, like human bodies do, I would definitely not want to live for 255 years. However, if that didn't happen until around 200, I would love to live that long, if only to see what life is like in 200 years.
I think on comfort humans get out of living is knowing when it comes the time for it to end, they won't be faced with having to deal with some of the consequences of human actions later down the road. It could also introduce more mental and physical diseases into the mix, if we live that long. I think the current age range is perfect for humans.
I do not think that i would want to live well over 200 years old like a tortoise. I can only imagine that the turtle was in alot of pain and tired from being so old. I know how i feel and I am certainly much younger than the tortoise. I think 100 would be the limit for me in terms of age.
I would be fine with living about 255 years if I were a giant tortoise. But if I were to stay human, I would refuse. Why?
Because (1) as a HUGE species, we already have even more humans every second! Without enough people dying at almost the same rate, we will quickly overpopulate Earth.
Not to mention (2) we tend to be extremely jealous of those who have more. If, say, I was the only one on this planet, Earth, to live this long, others would surely grow spiteful of the amenity they did not have. Note that 250 years does not have to mean immortal. So basically you would live UP TO 250 years as a maximum. Jealous humans could easily kill you as penance. And as we age, our bodies tend to 'break down', therefore at the age of 250, we may lose the capability to truly enjoy the many years given by the age of a mere 80.
Another reason: Climate change (3) is growing, and it's growing quickly. The world is getting warmer every summer. Proof of this would be the polar ice caps, which have already began to melt. I personally would rather spend 80 years in the perfect world then 250 years in an overheated, dying planet.
In conclusion. I am sure that in my "measly" years of life without this "power" would be just fine. Thanks for creating this opinion, glad to contribute.