Without doubt, hands down go get a Fasco. They are the undisputed king of framing nailers. Reliable, bullet proof and built like a tank. They will also take Scrails which can be a game changer for some. They are certainly one of the most innovative of current manufactures of pneumatic fastener tooling. Scrails themselves are a Fasco product and they released Lignoloc wooden nails a few years back - not as mad as it sounds. I scrawled a few construction forums before getting mine for some advice, the name that came up again and again (especially in the US where framed housing is the norm,) was Fasco. Hitachi also has a good name and came up a lot but Fasco always came up first form the pros who could back their words.
I have one of their strip framing nailers, a brad, finish and a pinner. Spares are available and prices aren't that bad either. RRP is usually fairly high but plenty of outlets to get good deals.
Be cautious of some of the battery variants, I looked at a well known brand and was warned off by the dealer as the firing pin had a very low operational life and wasn't a user replaceable part - it was a return to base job. That said, plenty of happy users out there.
And no I have no affiliation to Fasco............Just a happy customer.
