The discus, especially with winglets, is a very sweet handling glider and suitable for first glider. The ventus has a reputation for being a little more demanding. This may explain why used discuses are more expensive. Performance is quite close to 80 kts dry or 95 wet. Then, wave goodbye to the guys with negative flaps. OTOH you need a MacCready setting more than 4 or a booming ridge to want to fly that fast. Of course I'm biased because my discus is for sale!
The Ventus is certainly a higher performance glider than the Discus. However, it depends your experience.
The Ventus has a VERY special spin and stall behaviour. I wouldn't recommend it for an unexperienced pilot. Especially the version which doesn't have the Schempp-Hirth airbrakes.
It's gaining speed extremely quickly when it spins, with little warning such as buffetting.
There is no comparing an early Ventus and a Discus!!! I have flown both this year at Nationals, a Discus A (which is for sale, please email me if you have any questions about it), and a Ventus A. They are totally different gliders, the Discus is one of the easiest single seat gliders i have every flown. Very easy to fly, takes no thought (maybe thats why i landed out soo much). You can sit in a thermal and trim and basically hands off. I highly recommend one as a first glider, because they are easy to fly, also if you want to race you dont need to upgrade. I was flying against Discus 2's and and everyone else and the only thing holding me back was my flying in more sink more than everyone else. Chris Saunders got 2nd in a Discus A.
As far as the Ventus A goes....dont buy it as your first glider...you will never want to fly a glider again, and probably hurt yourself if you are low time. Please dont get me wrong i loved that Ventus A at Tonopah i did 12th overall and my first flight in any ventus was practice day 1 fully loaded with water. The Ventus is neutrially to negatively stable. In otherwords if you take your hand off the stick to go pee, when you look up your nose will not be in a heading that you wanted. If you tap the stick forward it stays forward, same on all three axes. the nice thing about it, is you have to pay attention, you end up really consintrating on keeping the nose constant and centering your thermal, because its like balancing on a basketball.
So if your hellbent on a ventus or discus, ask yourself do you want a glider that is really easy to fly, or do you not mind being worn out after a 4 hour flight. The prevouse owner of the Ventus said that after his first flight, he would never fly it again. I have heard that M&H winglets and factory ferrings do help the handeling of the glider a lot.
I had an '85 Ventus B. The stall/spin characteristics were fairly benign. In fact, I could only get a spin entry by forcing it with cross controls. I always flew with either winglets (Masak) or the 16.6m tips, and had the CG roughly 30% forward of the aft limit.
I have no doubt that some Ventii were a bit worse than mine in spin characteristics. I also have no doubt that some pilots may mistake a spiral dive for a spin (I've never experienced 'gaining speed' prior to spin recovery in any glider). In fact, if I let go of the stick in level flight, mine would enter a spiral dive in a few moments, with no particular fanfare.
The Ventus is most certainly neutrally stable (at best), and mine required a hand on the stick, and my full attention, at all times.
The trailing edge divebrakes takes some getting used to, and I had a couple of fairly amusing arrivals before I learned how to use them. One you do learn, however, I don't know of any other 15M glider that can land as precisely and in as short a distance.
Bottom line for me was that I fly for fun, and I wasn't having fun flying my Ventus. I sold it after one season and about 50 hours.
The first time I flew a Discus I fell in love. I would have bought one if I could have afforded one at the time. The handling felt absolutely appealing and natural. The one thing I haven't heard others mention, however, is that they land relatively fast (even for a standard class glider). Putting one into a short field can take a bit of skill.
This is only true for the early models Ventus A and B.
The Ventus-C handles much better and the Ventus-2C handles just as easy as a Discus or any other kind of kiddy glider.