Plusnet is just a different fronted brand for BT i.e. any traffic problems associated with bt happens to plusnet. Orange is undoubtedly the best deal without caps, but that said there are still options like adsl24 which still run on bt lines - but they all have some cap between 50-90GB.

PlusNet is owned by BT. Traffic is separate. Customer service is based in Yorkshire, UK. Many differences.
Traffic goes along the same pipes, has the same shaping as bt and one of bts largest call centres is in Leeds (i.e. Yorkshire). It's the same thing re-branded for people tired of bt.
Traffic goes along the same pipes, has the same shaping as bt and one of bts largest call centres is in Leeds (i.e. Yorkshire). It's the same thing re-branded for people tired of bt.

