As most posters have said, don't hesitate, go and buy one.
We have had a Neff 900mm wide induction hob for seven years and I just love it. Why? It heats up water for vegetables, for example, faster than the kettle, is SO easy to clean (no scrubbing necessary as with my previous gas hob) and is so responsive. Heat up or down, simple - it is as responsive as a gas hob but without the mess.
I continued to use the stainless steel pans (about twenty years old) so didn't need new but even if you do (test by putting a magnet on your pans. If it sticks, they're fine for the induction hob) the cost of a good set of pans is negligible over the long-term.
As to whether one can use all four hobs at the same time, well, I have five and I have had no problems (perhaps, those with problems simply have a duff hob?).
The only minor problem I have had is making jam whereby my large maslin pan won't heat up to 105 degrees - right for jam. It will only go to 100. This is easily surmounted by just boiling for a few minutes longer.
The ease of, for instance, melting chocolate without faffing about with a double-boiler etc., and general 'controlability' makes an induction hob with every penny - and then some. I would not change it for anything. Well, OK, perhaps a million or two pounds.... AND a cleaner!