I'm going to say it depends on a lot of factors. I was there by myself in March and started with the idea of RD one park with FP in the second park, but quickly nixed that in favor of refreshing.
However, I spend a massive amount of time refreshing. Not that there were not FP available, but that I was trying to get the perfect time or the best FP. Part of this was probably because I was by myself so it's a super easy thing to do while you are waiting, but, if I was with a group I would probably not want to do that and miss actually spending time with people.
So I would consider:
-how large your group is. The larger the group, the more intricate FP refreshing would be and take longer.
-how mobile is the group. smaller children, older adults and anyone who moves slower will make hopping and moving take longer
-what are your must-dos. If you can't get a 7DMT in advance and want it, you can probably get it, but refreshing is going to take a long time as opposed to stuff like Little Mermaid, figmet etc.
-what park you will start in and go to. You can RD HS at the crack of dawn and get the TSL rides, but, by that time, waits for RNR, TOT and ST are going to be huge. Are you ok bailing at that point and moving on?
-how long are you planning to spend in each park. I RD HS on and managed TSL right before the park opened normally. I booked it to TOT and a reasonable wait to come out to the fact that no shows were starting for awhile and everything had a wait time longer than I wanted(except muppets). That was when I decided to just schedule FP and refresh.
I would say on balance, I preferred to schedule FP in the park I RD starting around 9:30/10 and then see what was open in the other parks without a clear destination in mind. Again, this was easier on my own, but I got to ride FOP 4 times and SDD 3 using this strategy. Had I scheduled FP for my second park later in the day, I would not be able to take advantage of that.
The only exception, I would say, may be epcot because, if you can RD, you have a good chance of hitting at least 2 out of the 3 major rides and the smaller ones will have lower waits. I know some may disagree with me on that point, but it's my two cents.