Hi Maggie!
I use the Rowenta Expert Steam Generator (at home only) which cost me a bit over £200.00, but it is really good. The only disadvantage I find with it is that after every 10 irons I am supposed to wash through the generator tank which entails connecting a hose to the sink tap and the other end of the hose to the generator then turning the tap on for about 1 min and flushing out the tank. Pain in the rear for me as my tap is an awkward shape.
The other thing I find sometimes with the Rowenta is that when you first press the steam button to get the continuous steam flow going it occasionally spits out some lovely rusty coloured water.......probably not right (but this post has reminded me to email rowenta and query it).
However having said all that, I wouldn't be without mine, is cuts ironing time by up to half (depending on how creased clothes are). Bear in mind tho you will need to invest in a mesh ironing board (if you haven't already got one) as the amount of steam generated by these irons will undoubtedly leave your ironing board cover wet and your board rusty if it is a solid board.
Also remember to have a squirty bottle of water close by in case you iron a crease in by accident as these irons don't have the water squirt option!!
I have found on occasions, especially with t-shirts, that I need only iron one side as the steam pressure generated automatically allows the b-side of a T to be ironed.....most impressed!!
Tefal ones are good, look for one with the highest amount of grams per minute and high bar figure. Some of the better ones are about 3.5 bar and up to 150g per min.....