Have to admit I don't use the freebies because I use 11s (I give them to my nephew instead). But up until a few years ago I was a confirmed Rotosound user.
Can't rememeber how/why, but I got switched to D'Addario. I'll still buy/use Rotos in an emergency, though.
Ernie Ball's I always found too bright for me when they were new. Then they'd be "good" for a few days when worn in. Then they'd go off really quick for me. When I got into Rotos I found they were more like "worn in" Ernie Balls when you first put them on and stayed that way for quite a while before they went off.
I find the D'Addario's do roughly the same as the Rotos, but they "seem" to feel better for me, and they seem to last longer.
my experience is almost identical to andy's.
not keen on ernie ball's at all.
used to use feline strings, but found the low 50 too much for me. back on d'addario now