No jerking motion when walking or running. I bought it on an extreme sale thanks to the holiday and a whim.
It feels a little close to the front guard for where I like to run but it's no issue to just step a hair back. Inline and speeds work smoothly. I haven't played with bells and whistles. It has some, but I just like to get on and go manually. It's only a little weak at speeds sub 1.0, but after that it feels like nothing stops the belt. I'm not right at the weight limit but currently heavy and it works like a charm. If you can get it for a good deal, it's easily worth it (I paid about 1.2k)
Be aware that' it's heavy. comes on a pallet that the delivery guys won't want to drop anywhere but at your front door. Can't blame them. You'll need to open the items up and move them one piece at a time. You'll need two guys and some muscle to move it up and down stairs.
VERY easy to assemble. I didn't use the instructions until the end to make sure we didn't miss anything. Instructions are a bit wordy and as simple as this is, they really should have gone for an ikea style set-up. I think it took me 30 minutes to be 100% up and running and I was just having fun figuring out how to assemble.
Requires maintenance/lubing and recommends rubber mat under it partially for that reason. (don't want oil on carpet)
that's about all I've got. If you need a treadmill that works, this one works. Oh, and I think someone was complaining about some shocking issue... absolutely nothing on my end.