Mihai Parparita has done it again. Not only did he author my favourite (and prettiest) Greasemonkey script: Gmail Macros, he has now gone ahead and integrated Google Reader with Gmail, using only Greasemonkey.
Btw, talk about "throw it against the wall and see what sticks"... Greasemonkey is probably one of the best enabler of such technique!
I've imported all my RssFwd subscriptions over to Google Reader to try out Mihai's Gmail Reader. So far so good. A few kinks here and there (e.g. unread Feeds doesn't bold like other labels, Gmail Macros can't go to Feeds with 'G, F' keystroke) but no show-stopper, and definitely nothing an official integration wouldn't fix - if there is one.
There are differences between using RssFwd + Gmail and Google Reader + Gmail. In the former, content is "in your hands". Emails are plain old emails. Take them anywhere, filter them, fwd them, do anything to them. We've had emails for donkey years now, there must be at least a hundred tricks you can do with emails - and none of them requires any new features from anybody.
On the other hand, Google Reader (like most RSS readers) will need to work towards making such tools/features available. The lack of features that we take for granted in the good'ol email makes the content in such readers feel more... transient in comparison.
I guess its just a matter of what suits you. For me, I'm giving myself sometime to see if this Gmail Reader usage pattern groove with me :-)
PS: What/How long does it take for Google to officially integrate Persistent Search & Gmail Macros? Just do it already! *sigh*