Hi protege,
Sleepworld certainly wouldn’t be one of my choices in the Bay area (see post #2 here). There are some great choices in the area but Sleepworld isn’t one of them IMO.
2.5 lb memory foam is about the lowest quality you can find and I would avoid it completely with the possible exception of a very thin quilting layers (@ 1" or so).
3 lb memory foam is also very low quality/density.
I personally wouldn’t go below 4 lb memory foam and if you are in the range of 200 lbs or so than I would hesitate to go below 5 lbs if durability is an issue (except again for very thin layers).
1.9 lb base foam is better quality than the Sertas (1.8 lb is usually the minimum I consider to be acceptable … at least in the top part of a support layer and in a reasonable budget).
These are not good choices in terms of either quality or value IMO.
Phoenix