Hi,
Here's my view on it - If you're going very close to the voltage limit of the drive then a regulated supply is the correct choice. However, a linear, non regulated supply can usually supply 150-200% (the voltage will sag a bit though) of it rated current during short periods of time which a typical switching supply usually can't. Once it reaches its rated output current it'll shut down with an overcurrent fault - at best. Some try to restart automatically which can result in some interesting results.
This means that the switching supply needs to be sized for peak current while a non regulated linear supply can be sized for continous current.
That 7.3A switcher will (hopefully) live up to its specs and supply 7.3A but probably not more. Meanwhile you can count on the the 7.5A linear supply to easily give you 10 or 15A for short periods - a couple of seconds each minute etc.
If the switcher is 50% oversized as it is then I don't see any problems with using that though.
Well, that's my €0.02
/Henrik.