[Chrysalis]

I used to have ADSL and had it for 3 years, having since moved to ntl cable (forced to by landlord) I have not really has bandwidth problems but the email is terrible and the dns servers are the same, obviously the dns servers have a big impact on the service making everything perform poorly. Also my tv I feel is below par because ntl are effectively offering a different service depndong on where you live, my area is analogue tv only meaning I am getting a reduced service for the same price.

Ok now onto ADSL

there are a few different types of adsl services, starting with the 2 major ones.

20:1 ipstream adsl (commercial usually but not always the case now, more below)
50:1 ipstream adsl (residental service)

Both these are the standard type of ADSL service available in all ADSL enabled exchanges provided by BT wholesale, the 50:1 service is aimed at residental customers and is cheaper than the 20:1 service, currently the 50:1 service is available at 512kbit and 1mbit (trial). The 20:1 service was originally only for commercial customers with a very high price tag but it has since dropped dramatically allowing some isp's to resell it to residental customers, plusnet and nildram are two that I know off doing this, 20:1 is available at 512kbit,1mbit and 2mbit speeds. All ipstream services have 256kbit upload and are actually contended much lower than advertised by BT wholesale, users on the 50:1 service are yet to have any real contention issues any contention is normally caused by the ISP side of things.

next we have datastream, this is a new type of connection emerged recently and this is probably what caused BT to drop their prices for the 20:1 ipstream service, the difference between ipstream and datastream is that ipstream mixes different isp's customers together on a BT wholesale managed pipe and contends them, whilst datastream is just a pipe used by 1 isp's customers only. Datastream allows the isp to sell services at their own specification speeds, contention ratios etc. but because of the lower amount of customers on the pipe it is more expensive to provide and as such contention is usually much more noticeable on datastream services.

Isp's I know off using datastream are tiscali and bulldog. Datastream isnt available in all exchanges but is available in a lot more exchanges than LLU. Datastream is available in speeds upto 2mbit like 20:1 ipstream.

LLU is another type of adsl when the Isp installs their own equipment in the exchange and has a lot more control over the connection and exchange equipment.

This is allowing them to sell services at very flexible specification eg. 8mbit adsl.

Bulldog and easynet use LLU.

LLU is only available in some london exchanges and is been expanded to some major cities at the moment.

So there you have it this might not be 100% accurate but I hope it answers some questions, generally I wouldn't reccomend datastream I would defenitly go with an Ipstream service but with the drop in price on 20:1 ipstream you can get affordable 2mbit adsl on every exchange.