One trend on the Web these days is to move away from traditional full-stack frameworks (like Rails) toward client-side, full-stack Javascript frameworks (among them Dojo, GWT, SproutCore, and Cappuccino). There’s been a lot of buzz about SproutCore and Cappuccino, because of their design elegance, shiny Mac-ness and promises of really rich client experiences. I’ve been checking them out and here’s some of my observations so far:

• They’re both really young: SproutCore and Cappuccino have emerged only in the last three months. I haven’t heard of any deployed Cappuccino apps asides from the storied 280 Slides app. Same with SproutCore, looks like asides from MobileMe, they’re only beginning to see user-created apps come out (see: OtherInbox).

• The two frameworks are beautiful. Because they both model on Cocoa, they both take on the same icon set, window chrome, pane behaviors, and so on. Nice work, lifting the good UI work from the Mac and placing it on the Web.

• Objective-J sounds cool. I just can’t see non-Cocoa programmers just picking it up, though. Even though I picked up Cocoa over the summer and I think it’s pretty awesome, there was no way I would have the energy to pick up Objective-J on my own (unless Cappuccino proves itself to be THAT big of a draw).

• Okay, but to be fair, the idea of “Cocoa on the Web” is phenomenal. I wonder if we’ll see a surge of ported Cocoa-to-Web apps. Aligning Cappuccino with AppKit is a great idea, and it’s clearly the “Web framework for Cocoa apps moving to the Web” and you’re gonna want to use it for sure if you’re a proven Cocoa hacker. I wonder, however, if it can capture users who aren’t Cocoa programmers.

• I’m a big sucker for looks. Nothing gets me excited like SproutCore applications do in all their Aqua-like goodness. GWT in comparison looks pretty frumpy. I really like OS X-looking widgets. What can I say, I was brainwashed :)

• SproutCore and Cappuccino apps are simply not going to be able to out-perform GWT apps: they simply can’t beat the compiler optimizations of compiled and optimized JS in GWT. Then again… we’re going to have crazy fast JS engines in the next year or so. We’ll see if performance is an issue.

Even though these two frameworks are only beginning to gather momentum, I’m excited at the direction they’re moving the Web in. Anybody else want to weigh in?