I've done both, 1st fly, then batch, now fly.
I never struggled to get up to 85% when fly sparging and batch was around 80% (when stirred well). I tried batch sparging due to thinking it would be quicker, it wasn't for me, by the time I'd got clear runnings on the 1st batch top up addition, then the second batch, I might as well have fly sparged, so I went back.
Using HERMS for the entire mash cycle and fly sparging extraction was better, high 80's, but nowadays I use more malt than needed, and end the sparge high, so don't really bother with efficiency any more, recipes are based on 75% deliberately. I also sparge faster than a lot of folk at around 2.75ltr/min so I'm usually done for a 75ltr boil volume in 30mins.
I'd say it's personal choice