Well, colour me pretty pleased then. Living in the suburbs of the second city does have some benefits I suppose... never been more than a mile and a half from an exchange (and currently within a half mile), well served for fibre, means I / my family have been running at a solid 500kbit or more for the better part of a decade, and our typical download speeds (when not constrained by congestion further up the pipe, i.e. on the sending side or otherwise external to our ISP) have TROUGHED at about 2.0 to 2.5 mbit, generally sailing around the 5.0~9.8 level on Virgin's "basic" broadband, which has reached "upto 10mbit" for existing customers, now.
And my new, extra cheap ADSL (Plusnet) manages to clock a healthy 12-13 mbit or so, certainly offpeak and often in peak hours. I haven't noticed a slowdown in any form. Maybe it's dipping to a mere 1-2mbit at times but putting a top-priority QoS on the speed test sites, who knows. I haven't been twiddling my thumbs waiting for webpages to load. Some downloads have dragged a little, but given that the last one I thought "aw... come ON" about was Portal on the final day of it being free-to-download, I think we can assume that was server-side congestion. Even so, it still completed that 4Gb lump in approximately an hour and a half (I didn't pay THAT much attention, but it was certainly doing around 1% per minute at one point), which is a decent fraction of single-speed DVDR, aka somewhere in the high single digit Mbits.
(Oh god, I hope I remembered to do that after midnight... or my monthly daytime transfer allowance is going to have turned into a pumpkin, and that "free" game will have cost me £5 in bandwidth... That's the one caveat with this ISP - bulk downloads are best scheduled for 0000hrs thru 0800; Virgin's was that it would cap your speed progressively the more you DL'd in any one day, from 8am to 8am; do a HUGE amount of downloading, and you'd find streaming HDTV required you to pre-buffer about 10 minutes of each hour...)
It's quite pleasing to know that the "standard" these days is only a small amount higher than what we were (personally) getting 10 years ago... which at the time was a massive, earth-shaking improvement from dialup... and my current standard is not only 24x that old connection (kicking several shades of crap out of Moore's Law in the process), but 20x the national average. Heck, even a typical Sotuh Korean wouldn't find much to fault.