Hi ima,
Now that’s funny! I can relate though … except in my case it’s staying up late doing mattress research or answering posts in a forum. Either way though … I guess it keeps both of us out of “trouble” … or maybe gets us into trouble as in “don’t you think it’s time to come to bed!” 
The Tempurpedic mattresses are a little easier to analyze because they use fewer types of material. They are basically all made from layers of memory foam of different densities (4.1 lb ES, 5.3 lb, and 7 lb HD). The regular 5.3 lb comes in a softer formulation and a “regular” formulation. All of their mattresses use polyfoam support layers and most are good quality and range from 2 lb to 2.2 lb but some use lower density polyfoam in the 1.5 lb range.
Their mattresses are made up of different layers of memory foams of different densities and formulas to create different feels. All of these layers are listed on the Tempurpedic site which is one of the things they’re good at (EDIT: this is no longer the case and their specs may no longer be the same and they aren’t releasing information about any of their new lines). The 7 lb foam is more conforming (meaning that it can relieve pressure better) and generally softer feeling than the 5.3 lb memory foam but it is also firmer feeling to some people because it takes longer to soften, has a more “resistant” feeling against movement, and denser memory foams allow a little less sinking in … at least initially … which is why they’re often described as more “supportive”. This materials is used in thinner layers in various models to modify the feel and add to pressure relief.It’s also the most expensive of the memory foam materials. The regular 5.3 lb foam is the firmest in terms of softness, and ease of movement. Many people feel that this one too creates a “sleeping in sand” feeling. Some like this motion restriction “sleeping in sand” feeling and some don’t. Next down the line is the softer 5.3 lb formulation which is more responsive and softer feeling than the regular which is why it’s often used in the upper layers when you see two layers of what seems to be the same 5.3 lb memory foam. Finally the softest but least conforming is the 4.1 lb foam which is used in different ways throughout the Cloud series.
All of the Tempurpedics use somewhat less breathable memory foam than many other types so they would also tend to sleep hotter. This is why they use the “airflow system” in the base layers which is convoluted foam which in theory helps the layers to breathe. In practice though … the effect of this is somewhat limited because the convoluted foam is covered with less open celled memory foam so for the convoluted layer to work the air would need to go through the less breathable foam on top. Lying on a mattress also compresses the “channels” and limits their effect. The most effective “breathable” memory foams have a more open celled structure than the Tempur material and/or punch holes in the upper layers to help with airflow and help the upper layers “connect” better with any air channels underneath.
There is one exception to the use of combinations of memory foam comfort layers and polyfoam support layers in the lineup which is the Bellafina (NOTE: no longer sold in the US) which uses 3" of Dunlop latex underneath the memory foam and then adds the polyfoam underneath this. the quality of the latex is unknown but If I had to guess it would likely be a blended or synthetic Dunlop which is about the lowest cost version of latex even though low cost latex is still better than other foams.
So to compare a Tempurpedic with other mattresses in terms of quality and durability would be a matter of comparing the quality and density of the foams used in each mattress. In most cases I would tend to reduce or minimize the use of 4 lb memory foams for those who are over the low 200 lb range because they are less durable than higher density memory foams.
In terms of “feel” though … it’s a very different story. Tempur uses fairly sophisticated layerings of different types of memory foams to create a wide range of mattresses which not only feel different but cater to different sleeping styles and preferences. Their foams tend to be of the “less responsive” and “less breathable” type compared to many others but only lying on a mattress can really tell how these differences and the different memory foam layerings will feel to each person. One of the reasons that the iComfort has been so successful is that it uses more “responsive” and breathable memory foams (which some people … but not all … seem to prefer).
In general though … Tempurpedic uses high quality foams (keeping in mind that a 4 lb foam is always less durable than a 5.3 lb foam) but they are significantly overpriced IMO when compared to many other memory foam mattresses that use equal quality materials in similar layering. Each memory foam has a certain feel though which is independent of it’s quality so because Tempurpedic is so widely available and was the first to market … it has become the “standard” to which others are compared both in terms of quality and feel which they have used to full advantage in their marketing materials and in their pricing. A great deal of confusion in both consumers and in the memory foam market along with continual aggressive advertising has allowed them to maintain and even increase this perception … at least till recently.
IMO (and supported by more scientific information regarding foam manufacturing) … they are no longer the “quality” leader or the “feel” leader … however they remain the leader in name recognition and are a common “safe” choice for people who aren’t aware of other mattresses of equal quality that they can reasonably compare them to. The market is so confused that many people think “memory foam is memory foam” and compare the Tepurpedics to one of the thousands of “cheap” memory foam mattresses which use 3 lb foam and cheap base layers and completely misleading “tempurpedic comparisons” and when the Tempur feels and performs better than the cheap low quality “imitations” … they think that Tempurpdic is the “best” memory foam out of all the other choices. This is the consumer and market confusion that has allowed Tempurpedic to maintain its sales and profit margins and which until recently allowed them to keep increasing their market share and profit margins as well) even though there are many mattresses that compete very favorably in every meaningful category of comparison.
There are more thoughts about the Tempurpedic mattresses in this thread, about the Bellafina here, and some interesting observations in post #18 here.
This post is probably getting pretty long and it’s probably better to leave it by itself as a general “Tempurpedic analysis” so I’ll leave your other questions for a separate reply.
Phoenix