I've got a range of curve tracers and testers ... an octopus curve tracer, and it-3132, thaikits curve tracer (jojo2520), tek 576
Here are my thoughts....
Octopus V/I tracer - cool device look it up - very cheap to build and works good but has lotta limitations but good on the cheap, I think thaikits might sell one, but an easy diy project.
Low voltage low current tracers - ie eBay kits / peak etc ... limited voltage and current makes it useful for some applications but are very limited in the voltage and current ranges they can test. might be the solution for you but know the limits...many hook to scope XY
older Commercial / KIT XY scope units - units like BK precision, leader, heathkit, that hook up to scopes. these typically have wider voltage and current rages but, are time-consuming to set up to get accurate readings. Very functional and a cheap alternative to a full blown tracer, though, you can damage the units or the device under test more easily than on a dedicated unit by setting it up wrong. great for the serious hobbyist.
Professional stand alone tracers - in this i include the older Tektronix 575,576,577,370,371, and its more modern counterparts made by Keithly and the like. typical advantages here are high voltages, high currents, and more limits and safety features over the scope XY counterparts., as well as ease of use, and speed of use. defiantly the way to go if you're using it professionally for matching components, or characterizing production components, qa testing and so on.
there are exceptions to the above, so basically i am saying that you should know the voltage and current limits of what you are looking at and be aware of what safety features it has or doesn't have.