“It’s a big update,” he promised as he ticked off the benefits of  iPhone 2.1: fewer dropped calls, improved battery life, dramatically faster back-ups, new performance enhancements and – he added three times for good measure – “it fixes a lot of bugs.”

The update arrived as promised Friday morning, and with the exception of a few wished-for improvements that didn’t materialize – turn-by-turn GPS support, landscape viewing of e-mail and cut-and-paste chief among them –  it seems to have delivered the goods.

“It is much faster overall,” wrote “ghostface147” on a forum at AppleInsider, speaking for many who followed. “No scrolling lag, faster opening SMS and Safari seems snappier.”

In fact, the adjective “snappier” was used so often that it became a running joke – in part because the same term was used to describe iPhone 2.02, the software update released in August that left so many bugs unfixed.

“Here at Ars [Technica],” wrote Jacqui Cheng, in her review of the latest security improvements, “we like to think of [2.1] as the ‘make the iPhone stop sucking’ update.” (link)

But that doesn’t do it justice. The performance enhancements Jobs promised are real: apps load faster; backups that used to go on for many minutes are over in seconds; long contact lists that seemed to take forever to load pop up almost instantaneously; and so far, app crashes do seem less frequent.

There are also some nifty software improvements, the most significant being the so-called Genius feature. Unveiled on Tuesday on the iPod nano and touch, it lets iPhone owners find tunes that go well together and create compatible playlists on the fly. One caveat: the Genius icon won’t appear until the iPhone has been re-synced (see here).

Overall, the early reviews, while somewhat grudging, are almost universally positive.

“We’ll need to take some more time to finish testing the battery and phone call reliability,” writes David Chartier at Ars Technica, “but after our early experience with the new software, we’re confident enough to tentatively remove the beta badge and say that the iPhone OS 2.0 may have finally arrived.” (link)

Below the fold: Apple’s official list of the improvements in iPhone 2.1 Software Update.