If you want to have a good service and it is necessary for business, then go with BT or a cable provider. If you want to have lousy service matched with irritating customer service based in Bangalore then go with any of the cheaper alternatives. We have a few clients on the Post Office service and these haven't reported any issues to date but then again it is too soon to assess.
SHARK!
For every positive action, there's an equal and opposite government plan.