Frank: The E70 is a stunning machine. There is quite a bit of documentation online regarding the electronic "unlocking" of what is more-or-less two and a half CS80's in a fancy box, with a rotating speaker, two keyboards, bass pedals, a reverb, a wah/volume pedal, and a drum machine. They are amoung the big secrets of the vintage synth world, and can still be found at reasonable prices.
Keep looking for an S6! They sound great, and are incredibly reliable. If there does happen to be a problem, it's almost always one of the 30 or so tubes.
Yes, the Lowrey Cotillion does that strange vowel change trick. Quite freaky and original. It's like you're listening to some weird alien language that you can "almost" understand, but not quite. I swear that once, during a session, I heard it say "Let's Go". The strings are quite nice, but with the Omni 2 in the room, it's hard to compete.
The other Lowrey in the photo is our Lincolnwood TSO-25. It's the upscale Berkshire, and does "Baba O Riley" and "Won't Get Fooled Again" beautifully. It's also the model that Garth Hudson used, starting at Woodstock. GREAT volume/wah pedal, which works on the drums too!