Anything available to Aeroplan members as classic rewards will be available to MP members at saver levels. The ridiculously priced market rewards (I think that's what they are calling them now - whatever the formally named ClassicPlus rewards are now) are only available to AP members. But these type of rewards are very rarely worth redeeming anyway.

As previously mentioned, mileage tickets on AC will have far fewer surcharges when redeemed through MP than Aeroplan. I remember once looking at CMH-YYZ - charges would have been about ~$60 through MP, and ~$165 through Aeroplan.

Worth noting that short-haul rewards with Aeroplan do require less mileage. 15,000 miles vs. 20 - 25K with MP (believe AP short-haul is still based on a region system vs. MP where the mileage is based on distance - with the lower amount applying to destinations <=700 miles).