I have the panasonic 360 and use it for paper peicing. Not really noticed it not staying warm enough, but when doing this, I'm not using it for that long between "rests".
Number one gripe, it has a rather fast shut off time, so I try to keep an eye on it and bump it if I see it blinking (warning it's going to shut off). I use it by my side when paper piecing. It also has three heat setting, but I find HIGH works on the cottons.
I really like the point on both ends too. I have never used water in it so can't say how it's steam feature works.