Thanks for the feedback - much appreciated.
If it's stiffer than Permashape, it may not be for me, as I see no reason for that, for my use.
I currently use a 13 inch MT Permashape SS for laying on, so I may just stick to the same model and go up in size. Just been asking around to see if anyone likes any of the competition. Ox don't do a 16" (even though they're made by Nela), Nela's newest ('Elite') seems too early to call, Ragni Feather Edge looks OK, but a bit less width than MT, which might feel stiffer (and it's 0.8mm thick - I think MT Permashape is about 0.7mm). I like Refina's flexi 3, but their Finatex 1/2 (0.6mm/0.5mm)laying-on trowels don't seem to have many fans in the UK, so I don't feel all that inclined to risk it.
Permashape, as you've suggested, may end up being the default choice for me, after all!
Cheers.