considering 15 yr old Eggleston Andra's

Make sure ALL FOUR woofers were either refoamed (assuming these can be refoamed and I see no reason why not as long as the surrounds are the correct fit) or replaced with the newer rubber surround type. Replacing the woofers is an expensive proposition $1800 for a set of 4 was the quote I received from Egglestonworks.
I was going to get I's and upgrade (for all the reasons French Fries mentions) but ended up getting the II's outright because the upgrade path was prohibitively expensive especially when shipping was factored in - freight is NOT cheap on these 210 lb each babies...

Now all that being said, if you can get a set of I's VERY CHEAP with rubber surround woofers, send them to Eggleston and they will upgrade them to III's (yes the 3's)for $5K(plus shipping). That is an AWESOME deal considering that even a demo pair goes for $15.9K here!

Great speakers. Go for it!

I think the biggest question is..how much??IMO unless deeply discounted Id pass..The bass and weight is an issue as stated above..Plus tough resale factor

the issue IS how well the speakers were refurbished. my pair had original woofers which had foam surrounds. when the material started to disintigrate a bit i bought 4 brand new woofers (dynaudio) with rubber surrounds. the sound
took a nice step forward from that point onward. the mids and tweets are going to last a long time so that is not an issue per se.
andra I- great speaker but woofer sits too close to the floor. in the andra-II the cabinet is taller and brings the woofer up several inches higher. result is better bass and better definition in the lower mids.
the Egglestons really shine on good piano recordings, followed by any/all acoustically produced music. the tweeters are hard to improve upon in my mind.
the midrange drivers are a bit slower and less resolving than the newest mids in the andra III, made using carbon fiber. at least that's the theory since i haven't had the pleasure of auditioning the newest ones.
i don't know of a better all-round great speaker off hand in that price-range, especially used. but-- they are very heavy (210 pounds). also, the better the speaker cable used the more DEEP bass you can squeeze out of them. that could get very expensive though.