All 3 should do a good job. IMO if they have kicker/throwers, the Deere works better in tight areas, the NH on hills that you drive up and down. The Deere kicker going down hill will tend to throw bales at times straight up, but that is going down a steep slope. The NH thrower will tend to strip leaves off the outside of the bale. Also I think because of the auger Deere makes a much nicer bale. The ends of the stems seem to not be on the sides of the bale with the strings. NH wades the hay into the chamber every which way and about 1/2 the stem ends are on the sting sides of the bales.
Around here the biggest problem with the small square balers is most dealers now don't have people who know how to set them up anymore. Most of the farmers have gone to round or large squares. I've re-timed a couple of 336 balers that dealer mechanics timed off in the last few years. My experience has been that 95% of the problems are in the set-up with either brand. Depending on the hay the set up of the feeder forks, wedges, etc make a difference.
Both brands look over the bale chamber for wear and cracks, look the knotters and needles over good. Make sure they don't look like a needle struck the knotter or has been oddly repaired. Loot at the drawbars on both ends, for cracks and slop. The Deere look at the flywheel side axle, they seem to bend or break.