Assume that you have immortality similar to Dorian Grey, you don't age and can heal from damage, immune to disease etc.
Would it be awesome or rubbish?
The first hundred or years or so would be good, but then constantly learning societies new regulations, advancements to ensure you don't end up in a lab somewhere would be weary.
Would thousands of years of knowledge and eperience make up for the small steps evolution produce (probably, as seual selection is overtaking natural selection).
Then figuring out that the planet will eventually be destroyed, but would still be alive would start to get on your mind, as would seeing everyone you know die. It would be a very lonely life.
The effects on memory could be bad, as current memories are automatically scaled to long term memory and autobiographical, it would appear that the older you get the speed of current events would be quicker and quicker.
It would be pretty cool to be a master of all human knowledge (or thereabouts).