I still have a Garmin. Last time I updated maps it took several hours and attempts.
Yes, that was a problem in the past. A year or so ago, they seem to have upgraded their system. It now downloads and installs relatively fast (it takes maybe a half hour to update three units).
Battery life is poor and has a very sluggish UI. Plus I had to pack a beanbag mount when taking on overseas trips.
iPhone can go on vent clip mount which is tiny, because phones are thin.
That is because the phone is so tiny... and. in any event, the vents are in a position where you have to squint at the phone AND watch the road. One may as well be Texting.
I would say however that the Garmin generally does a better job of guidance at multi lane exchanges.
Yeah, I don't know how one can drive on major highways in major cities (again, I am speaking of BIG cities -- Chicago, Dallas, Los Angeles, for instance) without lane guidance. It is all well and good to expect a passenger to be the Navigator but that isn't always (perhaps never) practical. The speed and congestion doesn't give one much decision-making time. And signage... there are, quite often, so many signs cluttering the landscape that just sorting them out takes all the time available before it is too late. Oh! And California. Their signage is very logical once you figure it out. Unfortunately most other states follow a different logic. <rant> <rant> <rant>
But for searching for POIs both before and during trips, it's no contest.
Of course you need data but t mobile simple choice provides roaming data.
Our primary GPS Unit is a Garmin
nüvi® 3590LMT. We have had it for about four years and it is still a "current" model. Nevertheless, I have a newer model on order (as mentioned earlier).
Yes, the Garmin is so much better. Primarily because of
POI Factory. One of the major POI sets we need is RV parks. The number of Smart Phone Apps for that category is pretty puny. Gas stations (including Gas Buddy), rest areas, red light cameras, etc. are about equal for both devices, I suppose. However, the larger screen and being in the line-of-sight makes the GPS unit much the more desirable.
FWIW, I have had no "sluggishness"-type problems with the last two Garmin units we have had. The only issue I have is that the 3590 is silent when you miss your turn. It simply reroutes you but it is instantaneously.