I believe that with the current crop of Web technologies available in MobileSafari, apps like Hahlo, PocketTweets and Showtime could thrive as an alternative to their native counterparts if Apple allowed developers to adjust the scrolling/drag coefficient of Mobile WebKit. If you compare the scrolling speed of your Twitter timeline in Hahlo and Tweetie, the results are drastically difference. Tweetie feels like it effortlessly scrolls based on how much momentum you exert in the scroll action, while Hahlo is being constrained by a fifty pound weight on its back.
Jag vet inte om prestandan är det största problemet jag ser med webapp:ar. Vissa fungerar alldeles utmärkt, andra inte. Precis som med native app:arna i App Store med andra ord.