I've tried the SW sausages from Iceland. The normal ones and the Italian ones. I wasn't really keen on either of them, I found them quite rubbery, dry and a bit artificial-tasting (probably just because there's no fat in them to enhance the flavour). I've heard they're good for making scotch eggs but I haven't tried that.
I stocked up on the Porky Lights sausages the other day, which are my favourites at the moment (0.5 syns each). They're really meaty and the flavour reminds me of the sausages we used to get from the butchers when I was a child, yum! I also like the Tesco Healthy Living Cumberland Pork Sausages (1 syn each). Would much rather use syns on sausages that taste nice than eat syn-free ones that I don't enjoy