I've never used a Maxi-ball on deer. Around here (NY) Maxi-balls have a bad reputation for "over penetration" with little impact. They drill a small hole straight through and keep going, like a full metal jacket. A friend stopped using them on deer, but uses them when he hog hunts.
Round ball penetration is not a problem. I've only ever found one still in the deer, and that was a frontal shot that passed 31" through the chest, diaphram, abdomen, and was lodged under the skin on the back of the offside hip. The deer reared up and fell backwards, kicked twice, and it was done.
Round ball is what I now use. In the past I have used Maxi-Hunters (like a softer, hollow-point Maxi-ball), and they are very effective on lung-shot deer. I've also had lung-shot deer drop immediately with round balls, so I can't say they're any better under 50 yards, but I would guess (don't know) that they are a better choice at longer ranges.
I have decided to use the round ball because it does require more patience and it is a challenge to work around it's weaknesses. I hunt where I can't SEE a deer past 50 or 60 yards. If I was going after mule deer or antelope I would probably be of a different opinion.
Unfortunately there are occasionally the "good" hits that still allow a deer to put 150 yards on in it's final 10 seconds of life. Muscle shifts and tissue plugs the ball hole(s) and you've got a tough blood trail. No one wants it, but that's life.
All you can do is refuse to give up and put all your trailing skills to use. If you loose the trail fan back and forth, or spiral, until you find it again. I drag 20 ft of uncoiled 5/16" line (my deer drag) along with me so I can see where the deer is trending. If I loose the trail I drop the line. When I find another drop I bring the line to that point and resume.
The worst, knock wood, round ball trail I ever had took me 7 hours and I found maybe six drops of blood in that time. I finally found the doe in the absolute thickest cover on that hillside. The wound was in the front legpit just over the heart, the ball having clipped the leg bone and shattered it, and the deer had lifted that leg and hobbled, plugging that side with muscle, and the opposite side was higher from where the ball had "skipped" up off the leg bone and plugged with suet, lung and clotted blood. I knew it was dead somewhere and spent hours zig-zagging that hillside (lots of downed tops of trees from having been logged in the past, dogwood and brambles). It was maybe 120 yards from where it stood when I shot but I kept "missing" it as I crawled through that section.
