Do I upgrade to PT12 or not?

Hi...Im new to the whole AVID thing, but to keep it brief I purchased PT 11 back in may this year, with a free upgrade to PT 12 if I activate before 31st December this year. I am concerned as I have heard that as 12 is subscription based, 11 will truely be the last copy of PT one can "own". I run a home studio and aren't to keen to have to be paying a fee every year just to use this program. I am also concerned that I understand you cannot downgrade back to 11 once you activated 12. There seems to be alot of myths surrounding PT12 and I would be so grateful if anybody can bring me up to speed with the implications of making such an upgrade. I have tried to contact AVID directly, but I simply get nowhere.

Cheers,
Luke.

Do I upgrade to PT12 or not?