The estimated speed is a range rather than a specific number. They are probably quoting the bottom end of the range, i.e. the worst case scenario - just their way of managing customer expectations.

In reality you won't get a lower speed than you currently get with BT.

There are three stability options on Openreach DLM. AIUI BT choose the fastest. What Sky and TalkTalk choose I wouldn't swear to, but would expect Stable or Super Stable, (or equivalent namings).

I was with TalkTalk for 7 years without problem. Their phone/live chat is useless, almost entirely offshore. If I ever had issues I spoke to the excellent OCE's on their forums. They are UK based and very knowledgeable.

You won't get them to quote you any higher estimates though. Some ISP's quote the BTw checker low estimates, some go for the high, some go somewhere down the middle.
I recall with some ISP's they offer the high estimate if you have a managed install with an engineer, and low estimate for a self install.

In reply to a post by RobertoS:

There are three stability options on Openreach DLM. AIUI BT choose the fastest. What Sky and TalkTalk choose I wouldn't swear to, but would expect Stable or Super Stable, (or equivalent namings).

BT use Speed DLM profile.
TalkTalk use Standard DLM profile.

The only difference being the numbers of resyncs and ES allowed per 24 hours. It does mean TalkTalk lines are more likely to be interleaved, and on those lines a little slower.

DLM profiles are also confused by BT OpenReach and BT Wholesale naming them 2 completely different ways which crossover.

OpenReach = Wholesale
Speed = Standard
Standard = Stable
Stable = Super Stable

So TalkTalk tell you they use Standard DLM profile, but they don't use BT Wholesale at all, so they give OpenReach terminology.
BT/Plusnet use the Wholesale wording and tell you they use Standard DLM profile, but it's actually the Speed profile using the same terminology as TalkTalk.

I'm not aware of any residential ISP's who use the bottom profile. Some better ISP's will also change DLM profile for you.

Some good deals at plusnet right now

http://www.hotukdeals.com/deals/plusnet-unlimited-fi...

I was with Plusnet until last August and only got 1.85Mb up.

In reply to a post by j0hn83:

You won't get them to quote you any higher estimates though. Some ISP's quote the BTw checker low estimates, some go for the high, some go somewhere down the middle.
I recall with some ISP's they offer the high estimate if you have a managed install with an engineer, and low estimate for a self install.

I looked a couple of weeks ago...
TT offered you the bottom of the B range
Plusnet offered you a range, and gave speeds from the A range
AAISP offered from the bottom of the B through to the top of the A.

Obviously the speed won't really change when you move ISP. However, the most important perspective is what number they use when choosing to fob you off on a support call.

The long and the short of it is after another hour on the phone to TT where I did actually talk with a technical UK support manager is

For TT 76Mbps Fibre + Boost Incl. Line Rental the threshold that TT would consider they were defaulting on the contract was 25Mbps [one third of their Max]
They agreed that they indeed passed on the call setup charge and charged for 0845 & 0871.
I complemented them on their 24 months FIXED price offer and also their claim to offer new deals ongoing to existing customers too.

However, I declined to sign up to what was reasonable pricing not just for Fibre Broadband Boost but also their Anytime and International calling plans [despite having to passing on the call setup charges and the 0845/0871 calls.]

I may be a total pedant as it seems nobody else had voiced such objections, BUT I couldn't agree to sign up to their 76Mbps +Boost when their minimum level of service was 25Mbps before I was allowed to cancel the contract [note: this was based on the assessment of my line, YMMV]. I said I doubt their lawyers would refrain from enforcing the contract with gusto if the service dropped to 26-27 Mbps and I tried to terminate the contract. The guy said he couldn't argue with that posited scenario (however unlikely).

So, to finalise where I'm at and where I'm going, and I must add that without THINKBROADBAND.COM staff and contributors I would not have had such input,to help with my deliberations, however in the end I have ordered a solution from an internet and phone provider where the internet service is based on a service provided by Entanet and phone provision by bulk purchase directly with Openreach which in total is a bit more expensive than I had planned and which won't see me in the ranks of the 80/20 club due to the limitations of my line, but potentially better than what I have now with reasonable line rental and call charges.
Thanks all for your patience and I apologise for posting the entire webchat with TT but maybe those who cared to plough through it realised how pathetic the dialog was.

Also worth checking what they offer on www.bt.com/myoffer

I am being offered BT Infinity 2 for £33.49 but for 18 months rather than 24 (currently have Infinity 1) which may suit someone who doesn't want to be locked in for as long as 2 years

What does the BTw DSL checker quote you under the downstream handback threshold column?