I once was able to try the Westin Heavenly Bed mattress with pocketed coil springs while staying at Westin hotel in LA. At the time, the mattress I had was not exactly top notch and I was really impressed by the level of comfort the Westin's mattress provided. You can try this mattress before buying by simply spending a night at a Westin hotel where these mattresses are used.
So even though I was going to purchase my replacement mattress from the Sam's Club (Serta), I decided to get the Westin Heavenly Bed mattress instead.
What Is the Westin Heavenly Bed Mattress
Prior to placing my order, I learned about the Westin Heavenly Bed mattress online. The mattress and its boxspring are produced by Simmons. Similarly to Simmons's Beautyrest mattresses, this model utilizes individual coils that insulate one person movements from another. In other words, unlike the regular mattresses, these do not transmit motion and vibrations as much.
The mattress has a 13-inch pillow-top design with a box spring (a.k.a. spring unit), which is available in two profiles: regular (8 3/4 ") and low profile (5 1/2"). I got the 60x80" Queen size with a regular boxspring, but other sizes are obviously available (Twin, Full, Split Queen, King and California King). As a side note, I live in California, but I am not its King (at least not yet), so purchasing a California King mattress might be a future option.
After receiving the mattress, I confirmed that it is very comfortable, just as I remember from my stay in Westin hotel. It is relatively firm overall, but the pillow-top makes its top part cushy and comfortable. The pillow-top is coddling the parts of your body that touch the mattress and it is a feeling that is most appreciated in cold weather.
The use of individually-pocketed coil springs does, indeed, insulate one person's movements from another rather well. I tend to turn a lot when I sleep and I wouldn't want my wife's sleep to be disturbed by my movements. The individual pocketed coil springs, of which the mattress has over 800, work well for the movement insulation. Not perfectly well, but well enough and much better than those of the traditional mattress.
I had my concerns at first about the durability of this approach. It seemed that the individual coil springs would be more susceptible to becoming gradually permanently compressed in some areas. Fortunately, it has not happened in the few years I had this mattress.
What happened however is the localized compression of the pillow-top. I used to sleep on the right side of the mattress and after about 1-1.5 years, you could see that some parts of the pillow-top became permanently compressed in those areas that held the bulk of my weight. Since, I switched to the other side and might switch back again, because the prior compression seems to have been remediated by time. Surprisingly, the side I am on now does not seem to be affected, even though my weight has not decreased (unfortunately, it is the opposite, but not by much). I weigh 185 lbs.
Otherwise, the mattress and its spring unit had stood the test of time surprisingly well so far, including a move. And I am a heavy user :) . The outer fabric is very durable as well. And for the $1,630 I paid it is a great investment.
Update 12/2011: The mattress is still in great shape and should last a very long time, especially considering that I dropped some weight and now weigh 172 lbs.
Update 2/2012: Unfortunately we had to dispose of most of our belongings, this mattress included. I since bought a similar Simmons Beautyrest mattress, but with no pillowtop.
Pros: Reasonable price, excellent comfort and overall durability, movement insulation, 10-year warranty
Cons: The pillow-top might develop temporary impressions and small lumps, not the cheapest
I bought my mattress at the Westin's web site, but it is sold at other places as well. I highly recommend this mattress and other Simmons Beautyrest mattresses (my mom has one of those and it is very similar in quality and comfort).