I replied to another poster a while back ago about the 4-post lifts we have in our shop. Here is a repeat of that post.
All of the 4-post lifts have some sway, ironically the lighter the load the more sway. I've found that the heavier the load on the lift, the more stable it is. We bolted our posts to the floor.
One of our lifts is a Backyard Buddy, the Cadillac of lifts in my opinion. The safety catches are designed differently on the BB and I feel are safer than the Dannmar D-7 (our other lift - a Chinese knock-off), but only because those catches don't rely on a stop welded to the post. I do feel the dogs on the BB could be better better designed to engage in a free fall - in that respect I like the D-7 better. Every lift vendor I've talked to will tell you horror stories about their competitor's product.
Keep the cables lubed with wire rope lube, grease the pulleys, and make sure everything that moves is well-lubricated and does not bind. Get the posts on the same elevation relative to your floor, and adjust the cables so that they are raising the ramp as close to level as is possible. When operating the lift, watch the operation and always make sure the ramp is coming down and going up evenly (level) - if it doesn't you will have a big problem as these designs can't handle these situations well. The biggest operational error is that the operator may not raise the lift high enough above the stop they plan on using before letting it back down on the stop - so when you lower the lift to the stop, not all of the 4 dogs engage the stop at the same level. That's why I say level the posts and the ramp.
These lifts and ones like them really aren't designed for commercial operation - they are made and priced more for the hobbyist so you need to be aware that they may not be as dependable (and perhaps not all the safety features)as the ones at the professional service centers, but if you know how they work and take care with the maintenance and operation, it should provide good, safe service for you.
By the way, I like the caster setup on the D-7 better than the BB. Good luck to you.