Hello
Currently running two 4.1.6mr3 bb servers. no issues etc. I was thinking about doing a inplace upgrade to version 5. Are there any key improvements, that I can use to justify the upgrade?

thanks

This is a really loaded question.
I would suggest going to BlackBerry.com and doing a side-by-side feature comparison to see what's new and/or different in BES 5.

Eva, here's are the direct links to help you save some time:-

Exchange: BlackBerry - Enterprise Server Compare - Microsoft Exchange - IBM Lotus Domino

Domino: BlackBerry - Enterprise Server Compare - Microsoft Exchange - IBM Lotus Domino

My gut feeling from what I've read is that if you can use the new features, it's worth upgrading. If you have no desire to use any of the new features, you're better off waiting.

Why?

I wouldn't upgrade at this point.