Originally Posted by
markandrew
Avios account does not link instantaneously so my first transfer took a couple of days while they checked that out, but my second transfer was in the worst case scenario the same day, if not immediate. If you may wish to use Avios at short notice then link the accounts in advance.
Otherwise, while you have an MR account and so long as there is no transfer bonuses, your points are best kept as MRs until you have an exact redemption in mind and availability confirmed.
I agree with posters above, the logic presented.. Keeping MRs for flexibility bookings on Aeroplan and not transferring until needed, or until a transfer promo is available such as Avios.
Its a shame that Amex MR points are not included with point transfer bonuses to AE anymore. Its been a couple of years now.