First of all, its worth to mention this thread:
Servos are what drive all the parts, its not a single motor, but many smaller ones. And these can be powerful.
Usualy with the OSR2 vs SR6 the main question is just: how much do you want to spend. The more you are willing to spend, the more likely the SR6 becomes worth it, especialy if you are looking to go with high quality VR devices. The extra axisses it provides on their own dont do a lot, but its still just that bit extra which helps especialy in VR.
What i would say is:
Quality vs price wise the OSR2+ wins by a huge margin, even without twist. The few extra axisses compared to for example a handy do a lot.
Quality on its own the SR6 wins. While it has more axisses, these are often not mandatory for a good VR sensation. The standard OSR2 does fine enough here. But if you have them, it still means a better experience. Its often just not worth the price.
And if we compare it to the handy, the handy loses at almost every aspect. The only part they have better is its easier to setup, making it a very good device for beginners. Build quality wise its still very good, and while speed wise it lacks a bit to the OSR, its still a fast machine. In most cases the lacking speed wont be noticed.
Even if we consider just single axis scripts, the OSR can perform these fine. But even then, some filler movement on the extra axises does a lot. Speed wise, the OSR beats the handy by a huge margin. And safety wise the OSR gets an even bigger advantage. But in the end, most scripts just dont need that speed. And if they do, its nice that you have it, but its often equaly fast numbing.
Sleeve wise, the OSR has handy adapters, which while it does technicaly mean they can be compared, to my experience i just prefer fleshlights more. So i am very likely biased here. But when it comes down to it, they are equal when its just plain up/down movement (the OSR technicaly has a small curve, you dont notice it).