Hi bw1985,
I or some of the more knowledgeable members of the site can certainly help you to narrow down your options, help you focus on better quality/value choices that are available to you either locally or online, help you identify any lower quality materials or weak links in a mattress that you may be considering, act as a fact check, answer many of the specific questions you may have along the way that don’t involve what you will “feel” on a mattress, and help with “how” to choose but only you can decide which specific mattress, manufacturer, or combination of materials is “best for you” based on all the parts of your personal value equation that are most important to you.
If you are choosing a mattress for a guest bedroom I would tend to look somewhere in the range of a medium firmness because based on “averages” this will “match” the largest part of the bell curve that would be suitable for the widest range of people.
I would also make sure that the mattress meets the minimum quality/durability guidelines here.
The Arctic Dreams is around the middle of the firmness range and uses a 3 lb high performance polyfoam comfort layer and a 1.8 lb polyfoam base layer so there are no lower quality materials or weak links in the mattress that would compromise the durability or useful life of the mattress so it certainly meets these criteria.
You would have a very difficult time finding a mattress that uses the type of high quality materials that are in the Arctic Dreams for $300 or less (queen size) because these are the type and quality of materials that you would usually usually find in higher budget ranges and it would certainly make a great quality/value choice.
Phoenix