The problem with all this automatic stuff is that it may never actually do anything to help you identify the actual root of the problem and even the alleged better plan is a train-wreck to begin with. For example, if you aren't updating statistics on large volumes of data changes, either the new or old plans could be absolutely horrible. And there may be no good plan to be had because the ORM created a non-sargable bit of code that must recompile every time it's used (like we had) and it takes 2 to 22 seconds with an average of 7 seconds to compile each time.
Yes, I agree that such automatic selection can help with occasional bad parameter sniffing but make sure this magical cure isn't giving you the nice-warm-fuzzies about things that you really should be proactively looking for and fixing instead.
Absolutely true Jeff . Held similar views about statistics update on large volumes on a poorly designed fast increasing group of large tables (the largest is at 135 million rows increasing by over 1 million per day).Though there's a manual update every 24 hours stats become stale because of the volume of data change (not large enough for SQL server for auto update).
Arshad