yesterday i had to fix an error in a large VB file (> 8.000 LOC, Visual Studio 2008). With R# turned on it was nearly impossible to navigate in code with the cursor keys. Sometimes it takes more than 5 seconds after a keystroke after the cursor reacts, specially if you use the automatic repeat by holding down the key. While navigating the cpu load for VS was nearly 100%. Additionaly to the size of the file there are many code issues for which R# have to generate hints and warnings. Also intellisense was nearly unusable because it takes up to a minute until it appears. Sometimes VS is frozen until intellisense pops up, sometimes i can break and continue editing.
The performance was much better in former builds and decreased significant in 2155.