Second day in Ubud, fifth visit here last 4 years.
So today twice I used Grab in/around Ubud. Yes, I know that local taxi mafia succeeded in banning them in Ubud as well as in DPS. However, you CAN find cars with grab if you bother to open your app and do the booking. And you SHOULD do it, here is why.
First trip was from the center of Ubud to Tegallalang, where shops are (visiting them was complete waste of time, but it is another story). So we went at this corner 'taxi booth' and asked price. Was given 180K ONE WAY. When I started to walking out, price dropped to 150K but that was it. So I opened app, and after waiting about 7min until the driver managed to get thru Ubud traffic I and my companions were on or way. Price for trip - 40k IDR. So, originally I was quoted 4.5 times of Grab's price and even after 'discount' it was still >3.5x Grab's price.
Once we got there and figured out that this was not the place we've been looking for, then the question came how we could get back. Keep in mind - this is not a touristy place there there are no booth with tours/taxi/etc. So we had to walk down for about 30-40 min until I managed to get another booking with Grab to take us back to Ubud. Price - 30K. And I did give to the driver 20K tip.
Now, regarding the experience. I asked both drivers and despite the language barrier I understood that nobody forced them to work with Grab. It is their choice. Then - both cars were clean and good condition. Thirdly - about prices for trip - I wrote above.
If we, travellers, submit the the 'arguments' that Grab (and Uber before) are taking livelihood from 'poor taxi drivers' than I can tell you thank we will be doom to be cheated, scammed, etc, etc, etc. I personally do not buy these arguments and suggest you do the same.
P.S. Grab's price to get from DPS to Ubud is $170K. It is 300K if you arrange with driver (recommended in this forum) in advance and 500K and sky is the limit if you try to get 'taxi' at the airport.