Hi Krandall,
I’m not sure what you are referring to by “negatives” but two twin XL mattresses can certainly be one of several good strategies for couples that have a very wide weight differential or have very different needs and preferences (see the first part of post #2 here). There are also some comments about the pros and cons of a split king mattresses (two twin XL mattresses placed side by side) vs a single king size mattress in post #8 here and in this topic.
There is more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of PPP in post #2 here that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for once you actually sleep on your mattress.
There is also more about the most important parts of the “value” of a mattress purchase in post #13 here that can help you make more meaningful comparisons between mattresses in terms of suitability, durability, and “value”.
When you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart who can help “talk you through” the specifics of their mattresses and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs to different body types, sleeping positions, and preferences or even to other mattresses that they are familiar with than anyone else.
When you are down to finalists that are all choices between “good and good” (which you are) and none of them have any lower quality materials or “weak links” in their design (which they don’t) and if there are no clear winners between them then you are in the fortunate position that either of them would likely be a good choice and post #2 here can help you make a final choice based on your local testing or mattresses you have slept well on, your more detailed conversations with each of them, your confidence about PPP and the suitability of each one, their prices, your preferences, the options you have after a purchase to return or exchange the mattress, any additional extras that are part of each purchase, and on “informed best judgement” based on all the other objective, subjective, and intangible parts of your personal value equation that are most important to you.
Phoenix