How much difference does an expensive putter really make?

I'm currently playing my best golf ever..... and alot of this i do feel is to do with my putting. I had 3 birdies in my round yesterday (first time ever) and they were all 4-6 foot type putts, so fairly pleased. I currently have a £35 no named mallet style putter in the bag but can't help looking at the shiney new expensive putters on certain golfing websites.

My question is, will an expensive named manufacturer's putter really make much difference? But really, from 6-10 feet out, will a Ghost Spider or Scottsdale TR, not to mention a Scotty Cameron really make all the difference?

but a putter, one that a golfer is comfortable with can serve a lifetime?

What do you think? Has it worked for you? Any advice is much appreciated.