It would seem that you were highly regarded at your previous company and as the main cause for your leaving will no longer be around there doesn't seem to be any obvious reason for not going back. Most people change jobs several times during their working life and if you were otherwise happy there and think they can offer you job advancement, perhaps it's better to opt for the devil you know rather than the one you don't, especially if they can offer you more short term security. In two or three years time you may well be thinking of moving on for advancement anyway, whether you moved to a different company or your old one.