Re: Chuck?
Like many woodturners, I have several chucks but still lust for more. IIRC, I have three Vicmarc chucks in various sizes. I also have, IIRC, three Record Power chucks, which are a clone of the Nova chucks. I have also had several less expensive, 'house brand' chucks. The ones from PSI were junk. I could literally bend one of the 'standard' jaws with my thumb. The Woodriver chuck I got from Woodcraft (I was in the middle of a project and needed a set of smaller jaws. Buying from Woodcraft allowed me to get the project done that day.) The Woodriver chuck was better quality. I still use it occasionally. With that as background, here are my thoughts on chucks:
First -- You most likely don't need a chuck. Chucks are convenient and I use mine a lot, but there are lots of other ways to mount work to your lathe. Some are actually better than using a chuck. (Lyle Jamieson has a great DVD on turning bowls. In it, he explains why he believes using a faceplate with a glue block is better than using a chuck.) Previous generations of woodturners were turning the same things we make today long before chucks for woodturners were invented. I wish I had learned these methods before buying my first chuck. If I had, I'd be better prepared for those times when a chuck won't work well. I also might not own that Woodriver chuck.
Second -- While I really like my Vicmarc chucks, I don't believe the 'extra quality' Vicmarc provides is required. My Record Power chucks do the job just as well. So, while I think Vicmarc, Axminster, Sorby, and Oneway chucks may be better quality than Nova or Record Power, I wouldn't encourage anyone to go with one of the premium brands unless there is a need for it. For example, one of my Vicmarc chucks is larger than any chuck Record Power sells. For larger work, I always use the large Vicmarc. Or, there may be a particular jaw set that's available for one of the premium chucks that isn't for the Nova or Record Power. (That's very unlikely. The Nova, Record Power, and Sorby chucks all accept the same jaws. Among the offerings from those four brands, you should be able to find the type of jaws you think you need.) Having said that, I'd stay away from the no-name and house brand chucks. They're generally not that much less expensive than the Nova and Record Power chucks when on sale, but the quality of the lesser expensive chucks can be a gamble.
Third -- I prefer a 'closed-back' chuck. I've had some of mine for more than 20 years. I opened the back of one of them just to see if any preventative maintenance was required, and it was pristine. So, I believe the closed-back chucks require less maintenance than the open-back versions. More importantly, the closed-back chucks use an Allen wrench to tighten. The open-back use a chuck key. Not only do I find the Allen wrench more convenient to use, it's easy to find a replacement should it be lost. That's NOT the case for a lost chuck key.
Fourth -- While my Record Power chucks serve me well. If I buy any more chucks, they'll most likely be Vicmarc chucks. Why? I like finely made tools. Remember when wrist watches were powered by a spring rather than a battery? Back then, a Timex watch did the job well. But, once I could afford one, I wore a Seiko. That's how I feel about my Vicmarc chucks. YMMV.