If you're primarily more interested in cornering, I'd say the track day (or possibly the Total Control class - I've not taken that one myself.) If the track day offers an instructor, or you can bring someone well above your level, to watch you and give you pointers all the better. Track days also help you get more brake control which is useful on the street. There is some risk involved. Crashes do occasionally occur during track days, though they normally only involve one bike in the beginner's class.
The MSF Experienced Rider basically gives you practice at more 'advanced' street riding techniques, such as riding over objects in the road and possibly some scenarios you've not yet encountered (or even thought of). This course involves much less risk. Usually the worst to happen is you drop your bike.
-Never mistake kindness for weakness.
-Harley Davidson rEvolution engine (V-Rod): Designed by Porsche, detuned by Harley.