Hi Saraturner,
There are too many variables involved that can affect how pressure relieving any particular topper will be on a specific mattress or for a specific person to be able to predict which one would be best for you based on specs or “theory” (see post #4 here). When you can’t test a topper in person then the most reliable source of guidance and information about the feel or firmness of different toppers will be a conversation with a knowledgeable and experienced retailer or manufacturer that sells them and is familiar with how their memory foam toppers compare to other toppers on the market. If they are familiar with both of them then they may also be able to help you compare them but if they aren’t then your own personal experience on both of them would be the only reliable way to know how they compare for you.
I can tell you that a higher density memory foam or gel memory foam topper will be more durable and that the Aerus would likely feel softer but softness isn’t the only factor that can affect how pressure relieving a memory foam topper may be for you.
When you are considering a topper that you haven’t tested in person then the return or exchange policy can also be a more important part of the “value” of your purchase so that if either of them isn’t “pressure relieving enough” for you that you have the chance to return or exchange it.
Phoenix