Agree if you have a likely busy travel year using AC planes, then worth $2.5 to 5000 in upgrades alone (actually more in dollar value but I wouldn't pay more than 2.5 to 5000).

The extra Aeroplan miles are sometimes seen as a burden (since I have way too many) not a bonus but that's just my view of the IKK cutbacks for travel outside North America. At least my daughter can use them effectively as she books further out for international trips so it all works out for me and I also give them to a charity I work with.

There are other benefits to SE of course but upgrades are big one for me as I have upgraded 99% of my flights since being a SE in every year since 1998 (once they had upgrades). I rarely by F/J except on UA and CA in Star.