I fell in love with Miss Firefly in the catalogue through looks alone (I also deeply desired the fabric they used there, but DH veto'd it 
). We went to the nearest Sofa Workshop - Bath (a round trip of about 175 miles!). I regret to tell you, Miss Firefly is NOT comfortable. I seem to remember the back was too 'hollow' feeling - it is sprung like a lot of theirs, but somehow gives too much and you are suddenly reclining back too much. We tried Miss Clementine but as Jenroy says, the arms are too low really, unless you want a low-armed sofa.
We ended up with Archduke, a new design. I love the look of it (it has an arched back) but I have to say, I do have issues with it. We opted for feather and a bit of fibre in the seat cushions. We knew this would mean plumping every day and we do this religiously. BUT
as much as I plump (and we're talking boxing the sides, dropping it end-on to the floor etc) as soon as you sit down, it all deflates and you are sitting on a hard, compacted slab of feathers. I honestly think their filling is not up to scratch and they use inferior feathers (which, incidentally, are already coming right through the cambric inner cushion and out of the outer cover). They are too crunchy and just compact. You get a lovely fat look when you've just plumped, you do get an 'ahhh' sensation when you sink down, but within 30 seconds, you're sitting on a hard-feeling surface. I wish we'd opted for foam, really.
I'm taking the seat cushion back to the showroom to show them it's 'unfit for purpose' but have heard stories about their customer service and am dreading it, frankly.
Not saying their sofas are all rubbish, and the designs are stunning. But definitely go and try a few times before you choose, and think seriously about the feather option.