I bought a Ender 3 Pro 3D printer. What are your thoughts on which Slicer will work the best with it.

try simplify 3d. i use this with my cr-10 i have so much control over everything i do.

I use both Repetier Host and Cura on my machine. Cura for surface ironing for that perfect flat finish

try repetier-host ive been using it with my ender 3 and works perfect

I downloaded the Cura slicer which I used to print a Nav Radio faceplate. the results were absolutely awful. I used the default settings, one of which Was 20% infill, obviously a very bad number. I am going to try a Nav Radio backplate today with a 100% infill setting. I suspect this setting is the culprit. I did a couple of smaller items with the printer and was very pleased with the results. The fit, finish and rigidity of the printer is 100% satisfaction with the exception of the Z axis lead screw. I did the shim mod and then immediately printed the shim upgrade piece from Thingyverse. The shim printed beautiful.

Same here. I initially was using the creality slicer software that was on the micro SD card but have since watched several different tutorials and all were using Ultimaker Cura which is free to download and gives a lot more selectability when printing components which provides superior exterior finishes. Highly recommend it and I am also a novice relatively easy to use