From Gosling (March 17 2010)

James Gosling is quoted in this article in the ServerSide to have described the features of JEE 6 centering around the modularity that comes from the use of OSGI Blueprints.

He's presented as being pretty positive on the whole affair.

 

From SDTimes (April 15th, 2010)

The article titled "From The Editors: OSGI Is Too Complex" quotes two main players in the OSGI world, "Milinkovich and Maven creator Jason van Zyl" as both saying that it's a couple years before the tooling is ready to take OSGI to the next level. Mike Milinkovich heads up the Eclipse Foundation. Eclipse is probably the most prominent application based on OSGI to date, and certainly one of the most mature OSGI tool sets.

 

From the Tycho User Mail List (Tycho is OSGI for Maven)

This is a direct copy and paste, with emphasis added by yours truly:

[Tycho Users] Several issues moving from PDE build to tycho build
Reply
Sievers, Jan to tycho-users
Apr 29
tycho documentation is less than perfect right now.
your best source of information is to do a grep on the sources

Ouch! Grep on the sources to figure out how things work? Yup. Sounds like a couple years to me....

 

and...from the trenches 

It took my entire work week trying to figure out how to get a prototype maven/osgi/everythingElse project, and it's related build, to work just the way I like it. Kicking my ass. I'm really learning a lot though, even if it's a lot more than I really wanted to learn. No. I am not done yet, I'll bet I got another week, easily. More tools to try, more questions about why certain patterns I'm trying aren't producing the results I expect, yada yada yada.

I've got no choice, there are some features of OSGI that I'm not willing to do without, whatever it takes.

Apparently, it's going to take a lot. I'm a lazy developer. This is not for lazy developers.