[Closed] Hosted VoIP phone systems

Does anyone have any experience of these. I need a new phone system for our office and had looked at 3 suppliers who all recommended ip based phone systems but still running on "normal" lines (excuse the laymans terms).
I was about to press go on one of these systems when I got talking to a telephone engineer who recommended I look at hosted VoIP as it would cost approx 1/4 of the other systems. He said all the salesmen I talked to would have steered me towards the first system as they get commission on a 4k job rather than a 1k job and that hosted VoIP is just as good quality and as reliable.
Anyone got any experience of a "hosted" VoIP which I'm told is different to a normal VoIP phone running on standard broadband