Thanks Mario for this review - your write-up is very good and describes a unique material very well - I don't post here often but I did want to chime in here to add my personal experience of this kind of material.
I have had a sample of this stuff (branded as polymorph and bought from Maplins in the UK about 8 years ago) and as a modelling putty/plastic I have to say it's pretty useless.
When cooled it is similar to polythene (meaning it doesn't glue or take paint well if at all).
It is quite flexible but not enough that you could make decent casting moulds from it.
When workable (about 50-60degrees Celcius) it has a consistency similar to Blu-tac, but isn't the best to work with as its generally wet (hot water being the best way to bring it to temperature) and is quite elastic - stringing and deforming greatly before tearing.
When cooled it doesn't saw easily and isn't nice to cut.
I have to say the 300gr pot I bought ended up being used to make tools such as replacement handles (quite good to make a unique tool handle perfectly fitting your fingers - just squeeze when warmed!), making paint palletes, and a few small scale DIY/repair jobs - but none of it ended up as part of a successful modelling project.
Sorry to be a bit down in this, but I'm not sure it really has a place within our hobby...
John