Would you buy a Dahlquit-10 if one was available for purchase near you

Not for me. The Motorola piezo super tweeters drive me out of the room, and coupled with the rather low sensitivity it would just put them out for me. 

They could be a fun project for you though. Replace the super tweeter with a dome, or ribbon, recap the crossover, get a powerful amp, and you will have a very fun speaker. There are just others that I would pick ahead of it. 

Someone just recently posted they picked up a pair for $375 in great working condition. Bargain accordingly.

 I used to sell those back in the day, they did a lot of things right and improved greatly with electronics.. a Hafler dh 500 could make them sing.  They do need some room to breathe . Imaging is outstanding set up on their stands. Front to back depth was exceptional as well as sound stage .  I did have a friend of mine who had modded his with Sequerra ribbon tweeters along with some Janus subs. That was a pretty impressive sounding set up.  room to work.

I would get them if they were in reasonable shape and priced correctly.
B