I like both, but based on which was cheaper at the time I bought them, I started with porter cable. My first brad nailer lasted about 5 years. This past year I bought a new nailer and a crown stapler, both PC.
I'm not easy on tools. And although I would sometimes put in some oil, which may of been 10% of the time I should of, it held up well. The striker bar (not sure the proper term) which pushes out the nail, broke. I tore the thing apart and after looking at the situation, went and bought another.
5 years is not a long time. But I used it for a few thousand frames per year, which come out to about 36,000 nails, and over 180,000 in 5 years before the bar broke. I have nothing to judge that on. But it seems fair enough to say it lasted long enough. Of course it may of lasted longer if I hadn't dropped in on the concrete floor a few times.
I use a number of nail guns (it use to be kind of my business). I have two senco nail guns for rough and finish carpentry. they are great tools, although one is old enough to draw social security.
for staple and pin nailers I buy the cheap one's from harbor freight. I like to buy the two in one (shoots pin nails and staples) which when on sale go for about 18 bucks. I buy two of them at a time without the warranty (since I can never keep up with the paper work anyway).
If i am not mistaken my Riged crown stapler doesn't require you oil it. Plus the lift time warrenty I feel is worth it. My two brad nailers how ever are Poter Cable. I bought them before I found out about Riged.