I know nothing about the Central Machinery Jointer. There have been MANY topics discussing that brand and Harbor Freight tools recently, you might want to search through for some of those. I realize that you asked specifically about this tool, but I I wanted to give you another idea in case you hadn't considered it...
Sorry to intrude, but I noticed from your profile that you live within driving distance of York, PA. Have you considered heading down to take a look at the Yorkcraft 6" jointer. I am of the opinion that it is a good thing to try out and see a big tool like a jointer before purchasing. Hence, it seems that you might be able to do so at the Wilke Machinery showroom in York. I live three hours from York and made the trek and bought the jointer last year. It fit in the small car (the family Civic) and is a good machine for $299 plus tax. There is also another topic in this forum discussing cheap jointers.
P.S. In case you all were wondering by now, no I do not work for Wilke Mach or York. I'm an in a totally unrelated field. I just thought that the affordable jointer idea would be relevant here.
From your questions above, I gather that your view is that the lever adjuster for the bed is a detraction. I am unsure if I would classify it exactly as such. I examined a variety of different brands before deciding (mostly based on economics) on the Yorkcraft...these brands included Delta, Ridgid, Jet, and Powermatic (pipe dream, but worth drooling over). As I recall the Jet and Ridgid versions have wheel adjusters and the Delta, Yorkcraft, and Powermatic had levers. I found the levers to be just fine for me. I would have been a little happier with the wheel, but decided all things considered that the lever adjuster was ok. One selling point about the Yorkcraft lever was that it has a positive locking mechanism. I'm sure others must also, but at least it has one. I would suggest that you take a look at several other brands before going with the Yorkcraft...personal research is the only way to go.
As for the jack screws and knives...I have to confess that I thought all major brand 6" jointers had jack screws for their knives. I might have overlooked this when shopping around, but I'm not so sure now. I will say that I like the knife adjustment on the York because it has been accurate for aligning the cutters with outfeed bed. For the price that I payed, I could care less how long it would take to change knives and didn't consider this a criteria worth comparing between brands. And to answer your question, I have not changed the knives yet...but I really should. I'm kind of like that anyway and never have enough time to do all that I should.
Anyway, I hope that you do your homework and visit as many showrooms as possible and try out as many brands as you can. Don't take my viewpoint as an authority on this, as this is the first jointer that I have owned and, hence, have a minimal basis for comparison. In addition, they're ripping me to shreds in the other "jointer" thread, so I think a chunk of salt would be in order with my recommendations...
I read almost every post on this forum and I always read posts on Jointer. I don't remember anyone ripping you on this issue.
I will make another recommendation,
Don't waste money on a bench top jointer. They are worthless in my opinion. The only thing they will work on is very small stock, less than 3 ft long boards. it is as easy and cheaper to do that effort with a jack plane.
A floor model jointer is the basic minimum to get any value for you money.
I don't know anything about York, But, it is one of the many Taiwan import brands. And with this class of tool you could get a very good or bad tool from the same model. The culture in China is the quality is the responsibility of the buyer not the seller. So if the import company does a good job of quality control your OK. For a tool like that I would want to touch, and check out the tool I buy. so if you can go to the store and take a straight edge and look over the unit you intend to buy first you should get a good tool for the money.
Look for warped beds and fences. Look for the beds being coplanar and that as you adjust the infeed that it tracks parallel to the outfeed table.
Check the operation of the guard, and how easy it is to adjust the infeed table. Check the motor for the ability to wire for 240. Check the manual for clarity of instructions on adjustment and parts lists.
Then check on how easy it is to get parts. Are bearings standard sizes.
Just a minor disagreement with your post above Lou (and I am splitting hairs here)...the Yorkcraft jointer is maid in mainland China, same as the Delta.
And as to the the "shredding" I was referring to, that was in the New to Woodworking forum and it was warranted. :^) For the good of the board, everyone here is very particular and it helps keep the diaglogue going and the learning curve steep.