I share Mick's concern about the Q word! A little extreme perhaps, but I'd go so far as to suggest no engineer should use it unless it's defined by a specification. On it's own 'quality' is as meaningless as 'nice' or 'decent'.
Professionals define quality by considering the heavenly twins: "Fit for Purpose" and "Value for Money". To them buying tools that are better than 'good enough' is an egregious sin if it wastes money that could be better spent on something else. (An engineer does for a pound what any fool can do for a guinea.)
"Fit for Purpose" and "Value for Money" require purchasers to think carefully about their budget and what the machine is for. Mick's examples cover both ends of the rainbow. On a shop floor where down-time costs the owner money it's worth investing in heavy, continuously rated machines made to do protracted accurate work. The machine is required to pay for itself, and much depends on the accountant! In a home workshop almost any lathe in reasonable condition with the necessary accessories will produce acceptable results in skilled patient hands, and the machine doesn't have to make a profit. No need to satisfy an accountant, though wives can be even more troublesome!
To add to Hollowpoint's list, you might investigate Far Eastern lathes sold to industry rather than the made down to a price hobby equipment most of us go for. These higher specification machines aren't widely advertised and tend to be Price on Application but have a look at Buck and Hickman and Chester Machine Tools. I don't know of any hobbyists who have gone this route because it's so expensive. Expect 5 to 20 times dearer than hobby machines.
Generally high specification kit is much more costly. Be prepared for shocking prices! Myford will sell you a new Connoisseur for £9050 + VAT and carriage. This is more money than I care to spend on a hobby, so it fails my 'Value for Money' test. Last time I saw a second-hand Schaublin it was £12000 for a plain lathe, i.e no screw-cutting. The superb Schaublin fails my 'Fit for purpose' AND 'Value for Money' test, not because it's a poorly made heap of junk but because it doesn't do what I need and is way over my budget.
For the time being I suggest sticking with what you have. Learn from it. Does it do what you need or does it have intolerable shortcomings? Once experience reveals the answer, it's much easier to define exactly what 'Fit for purpose' means in your workshop, and whether or not it's worth spending money to fix it. Much easier to consider a replacement lathe when armed with facts. Who knows – the answer might be CNC rather than manual equipment.
Beware of perfectionism, in the absence of big money or a good dollop of luck, it can lead to perpetual disappointment. Nothing is 'good enough' for the man who can't compromise and hobbies are meant to be enjoyed. However, personality matters. My approach to making things is distinctly utilitarian. I don't care much about warty tools provided they do what I want. Others are irritated beyond measure by tools with shortcomings. Excellent craftsmen are often perfectionists who can't do their best unless the workshop is clean and tidy, tools are neatly organised and ready to go, stock catalogued, zero rust, machines lubed and properly adjusted, and nothing broken or worn. Their notion of 'Fit for purpose' is different to mine, and they're not wrong! Are you like them or me?
At the moment there is an affordable way of owning an industrial grade machine. Many ex-education and professional manual machines are no longer 'fit for purpose' in a world that's shifted emphatically to CNC. Industry are dumping them and the much reduced need to train manual machinists has resulted in super-duper machines being sold at bargain prices, well below their original cost, and often in excellent condition. Contrasts sharply with the same class of machine 30 years ago, when they were often only sold second-hand when 'beyond economic repair', or were too expensive for hobbyists.
Dave