To be honest its hard to compare with other people unless they are in the same street as you.
Quality of the line serving your property, and from the exchange to you will vary from street to street.
Also distance is an important factor too.

I went from BT who told me it got no better than them, to Orange who said they would do similar.
What I ended up with was an identical service.
We have Sky BB also, again identical speed, except when they throttle it back.

At the end of the day in the same property on the same line, its all about the hardware they supply, and if the ISP throttles back connections at peak time.
I would do my reseach on one of the ISP provider websites to see which providers do the throttling back, and which dont. And who provide the best routers etc.