Some considerations:
- In general, drop weights are cheaper than cranks, which are cheaper than electronic. To achieve this, it often follows that other components are cheaper on drop weights - string clamps, base clamps, mounting system and even turntable. It isn't always the case... but if you're looking at drop weights then do compare the model with others from the same manufacturer to identify where they may have cut corners.
- If the plan is to add a Wise, determine what work might be required. They simply slide onto a crank arm - it's as straight forward as tightening a few screws. You may need to drill holes to fit the mounting plate on a drop weight base. Might be a piece of cake if you're handy, potentially daunting if you're not.
- That said, the stability of the Wise if it were screwed to a base would be marginally better than if it's on a crank arm. I don't mean you to overthink this - the Wise was designed to be a crank replacement and in 99% of cases it works exactly as intended - but there is a specific scenario where if you lock the turntable and try to pull tension with the string at an angle it will make the arm bend. It's not a big deal, there are ways around it, I really only mention it as if the previous note about the effort to mount the Wise on a drop weight was off-putting, the trade off would be ending up with perhaps a marginally better solution. (I have a Wise replacing a crank. It's fine. The only time I've ever wanted to pull at an angle is with Prince O-Port racquets, and it's been a long time since I've seen one of those.)
- You're almost certainly going to string standing up. Either buy a machine with a stand or have a plan for what you might put it on. And if it's a fixed surface, there needs to be room to rotate the racquet. The dimensions of the machine itself are not the final footprint required to string a racquet. Machines are also heavier than you might imagine.