I just got through installing them on my car this weekend. I noticed a definite difference in the firmness of the pedal. You can modulate pressure more easily. However, given your description of your braking problems, I'd guess you have something else wrong with the system. Either air still in the lines or a fading master cylinder if the soft pedal comes and goes. I wouldn't mess around with that - even if you have to borrow money, get your brakes fixed.
On racers (real racers - without ABS; couldn't resist), the lines are essential because if you're gonna threshold brake, you have to be able to 'feel' what the tire is doing through the pedal. The stainless lines provide much better pedal feel. On the street, they're nice to have, they improve feel (if all else is working correctly) - but you won't stop any quicker. Given that mine had 22 year old rubber lines on it, mine needed to be replaced anyway. And the stainless lines weren't that much more than new replacement lines. Just be sure you understand what you're doing on the install. All kinds of air will get in the system on a brake line install. Further, if you're not careful - you can run the master cylinder dry - which is a big no-no as many can only be bench bled (off the car). So whatever you do, don't let the master cylinder fluid get to the bottom of the resevoir. I had to get some bolts of the right size to use as temporary plugs to stop the leaking while I switched lines over. And mine's more complex anyway as the car has 4-piston calipers on the front and a safety braking circuit which means that I have 2-stainless lines on each side.
I've got a pic of them on the car - shoot me an email address and I'll shoot you a pic.