Traded my Sig229 DAK .357 for a M&P45 about three months ago.
The 229 was a solid, reliable piece, don't get me wrong. I really liked the new E2 frame as well (though I also liked the old style). However, even though the DAK trigger was consistent and relatively light for a double action system, it was still much longer than I liked and it had a LONG reset. It feels pretty good when you dry fire it, but once you start putting rounds down range, you realize how hard it is to get a quick follow up shot accurately (unless you have the time and the money to put in a LOT of practice). I've also tried a 229 in DA/SA at a local range and just couldn't get used to it, so converting my Sig was out. I tried the M&P at the same place and fell in love instantly. Traded my Sig in and barely paid a dime in balance for the M&P. One of the best decisions I've ever made.
Sig Sauer is considered, along with H&K, to be the Rolls Royce/Mercedes of guns: High price and high quality. But to be perfectly honest, I'd say Sigs, as good as they are, are WAY overpriced. In terms of quality, accuracy, and reliability, I'd say that the M&P, Glock, XD, and CZ 75 series of pistols are just as good, if not better than the Sigs, and they cost about half.
If you really want a Sig, I'd strongly suggest the Pro series. They have the same feel as the 220-229 series, same trigger, same quality and reliability, but they have a polymer frame and cost about $500 (as opposed to the $900+ most Sigs cost).
One thing about Sig to beware of: Their customer service. Unless you're an LEO or military, they treat you like dirt and offer very little effort to help you. They also frequently, and without warning, change designs and parts, making their guns incompatible with accessories like holsters, lights, etc., and offer very little help with customers, even LEOs, who encounter these problems.
I have some Sig stories, but this post is getting too long, so I'll wait.