I think we are coming back to the same old chestnut in all these pro/anti GPS threads: have you got a decent moving map unit?
If no, then GPS gives you no more than an accurate KNS80 or similarly functional INS box.
If yes, then you get excellent situational awareness handed to you on a plate and it is pretty hard to get lost.
At night or in IMC, one's SA is dependent wholly on instrument interpretation and there are loads of ways to get it wrong with the old VOR methodology. INS delivers RNAV (area navigation) capability to any point (which I suppose in the old days would not have been in the database but would have had to be entered as lat/long) but unless this is combined with a moving map, you can still make a gross error. When GPS first came in, it made this process super accurate but there are still heavy jets flying which have a GPS but no moving map...
There are also lots of private pilots flying with cheap GPSs which have no moving map; you can pick them up in camping shops for peanuts. These people often turn out to be in the "anti" camp. I have never known anybody using a decent unit being anything other than delighted with the benefits.
Unfortunately the interfaces are not standardised and one needs to do some serious ground work to get familiar before using the thing for real. I have a Garmin 496 yoke-mounted (mainly for its "EGPWS" feature which is wired to the intercom for audio warnings) and while I have programmed routes into it, it is too clumsy and in an emergency I would use it only as a DCT XXXXX box where XXXXX is an airways intersection or a navaid.
One needs to keep a mental picture but when there are no visual cues even the best people can make a mistake and turn the wrong way etc.
A good moving map display is the key.