I don't think it's a question of morality. God made us in his image, not just physically but mentally. Like him, we have a constant urge to create, to expand. Discovering longevity is not harming people, nor breaking any written Biblical rules, so morally, I think it's ambiguous.
However, I certainly would not try out for such a procedure. The problem with this modern world is twofold: people treat it like it's becoming a perfect paradise when we are, if anything, inching further from paradise, and whatever their intentions, I think most modern scientists oversimplify very complicated things like the human body (yes, I think even those lengthy medical journals don't even begin to breach all that we have to learn about our bodies) and therefore tend to create half-baked results. I'm a writer, and have toyed with many ideas of immortality as a story device, and while I admit it could have some benefits, I feel it will in the end just become, like in my stories, the beginning of an ultimate form of racism, with the rich and powerful commanding life and death over the poor, or anybody who doesn't share their opinions.
Luckily, I believe God is supreme, and we all have our hour, and not any amount of science can change that. People who talk about 'playing God' seem to forget that, no matter how far we go, we never can come close to matching God. God is so vast that, even if we discovered how to create an entire cosmos with our science, we still would be specks to Him. After all, God made us in his image. While I personally don't like when people 'play God', as people call it, I think God likes to see us push our boundaries.
The thing I think that is the main problem with playing God is that we assume we know so much more than we really do, and because of that, we tend to mess things up rather than improve them. Oh yeah, and we overlook human frailty. I'll tell you what longevity is going to get us: a 150-year-old Kim Kardashian and dictators who don't die. And let me tell you, I don't want to live 150 years in a world with the Kardashians.