Buying second-hand, condition matters far more than the Maker or type of lathe. A problem with really high-end machines is the cost of spares: machine cheap, spare parts likely to be 'if you have to ask you can't afford it' expensive, or unobtainium.
By home workshop standards, the Colchester Student is a big heavy lathe, and see lathes.co.uk describes the CVA as having similar capabilities but being three times heavier. The reason being, the CVA is massively rigid, which is a very good thing for precision work in a tool-room, but money down the drain for ordinary purposes. It doesn't have any extra functions, just solid and built for hard work.
In a badly worn or damaged CVA the extra weight is just an embarrassment because it makes the lathe hard to move and the floor might need strengthening. In good condition, the machine will nice to use, and capable of accuracy you rarely need, but it's bulk might be a waste of valuable floor space in a small workshop. (Mine is single garage sized and a Colchester Student would be a bit too big for it.)
Much depends on what the lathe is for. If toolroom accuracy is essential, then a CVA is good condition will do the job, but a knackered CVA won't. Depending on what's wrong with it a knackered CVA might be good enough for ordinary general purposes, but in that case a lighter machine would be more practical.
Buying a Far Eastern hobby lathe gets most lathe functionality, but with limitations. Typically, the motors and electronics are rated for intermittent use, not shift work on a busy production line, they are relatively lightly built, the finish is imperfect and they lack many time saving features. But, if you own a lathe with a clutch, full gearbox, mechanical speed-control, auto-trips, best-bearings, coolant system, and power features, these are the things likely to go wrong and are most expensive to fix. Great when they work, essential if the lathe is earning a living, but maybe unnecessary in a home workshop.
Due to Covid restrictions I can't recommend a personal inspection, but normally it's best to see second-hand lathes cutting metal and to make sure all the controls work without undue slop and there are no nasty noises, smoke, hot bearings, or electrical tingles. (Take care – might have perished rubber power cables, pinched wires and other electrical horrors!) Doesn't matter who made it, or what the manual says, the value of the machine depends on how well it works.
Damaged lathes can be restored but doing so can easily become a hobby in it's own right. Good fun unless the machine was bought to get on with other urgent projects, that now have to wait until the lathe is fixed. Certain faults are much nastier than others – cracks, bed worn beyond a regrind, burnt out motor, difficult to get or expensive parts missing, special bearings etc. Many others just require persistence and a little cash. It really needs looking at.
Dave