I’ve worked at 3 different companies now that have used Business Objects R2 thru R4. I can say from experience that the jump from R2 to R3 was extremely beneficial.
The jump from R3 to R4 however , in strict Business Object terms, was not that useful, in fact in many circumstances has been harmful. If I knew then what I know now regarding R4 bugs and issues , I’d still have our company on R3. In fact, I still develop on R3 for 99% of our WEBI reports.
We do not use Hana, SAP BW, or any other SAP product. We also only use WEBI. No Deski, no QAAWS, nor Xcelsius at this time.
On the front user side, the benefits in WEBI 4 over 3 are mostly in improved controls with regard to hiding and conditional formatting/displaying of data. And the biggest IMO is the multi document ability where you can have multiple documents open in the same browser window.
The other big WEBI features are really on the server side with regard to performance and whatnot, but unless you are having issues with your R3 server now, you probably won’t even notice them much. (For example if you had a report returning in 8 seconds vs 10 seconds, that isn’t really worth a real-world improvement note in my book, even though it’s 20% faster etc…)
In your situation, if you’re not needing any of the new hiding/folding features in WEBI, or any other bells and whistles, I’d say stick with XIR3 for as long as you can.
One last quick note: 4.1 is definitely an improvement over 4.0, but stay away from 4.1 Patch 1. This patch breaks WEBI date prompt controls and you will be getting unreliable results in your data (It actually changes the SQL prompt value sent to server). Neither Patch 2 nor Patch 3 fixes this issue. (And oddly the BOBJ world seems pretty quiet on this, not sure if people haven’t patched yet, or if they haven’t noticed the error.)
UPDATE-
SAP has acknowledged this bug. Fix is pending Patch 5 for SP4.1
JPetlev (BOB member since 2006-11-01)