I have had some great results rollering gloss, it goes on without lines etc, no hairs to come out of the brush etc...
If you do go for gloss, only take out enough paint to do a few panels at a time, reason being, when it starts to set, or thicken up, thats when you start getting some REALLY crappy finnishes.
All this painting talk makes me want to got and paint the steel runner round my tub! But no, its raining AGAIN. Could go and play in the puddles though!