This set has some sentimental value to me. As a kid (I would only have been 4 when it came out), my mom took me shopping every week. And every week I saw this set and thought how cool it would be to add to my 6085. Unfortunately at that age I was too young/shy to ask so I never got it (but it is now on my wish list!).
IMO it would make an amazing barbican for the Black Monarchs Castle, or indeed any castle gatehouse. I'll have to try that one day when I get the set.
The catapult is neither use nor ornament. It doesn't look as realsitic as 6030 nor does it work as well as the likes of 6039. i.e. it's the worst of both worlds - it looks bad and doesn't work. I also dislike the large black counterweight - it's too big in relation to the rest of the machine.
The large brown doors always enticed me as I drooled over this set as a kid. They looked so formidible. However, on closer inspection I can see that they open inwards. This means that any battering ram etc could easily break the doors. The design could be much improved if a large bar were supplied similar to the prision in 6080 to "lock" these huge gates.
Another weakness is the narrow walkway above the walls. I didn't mind this in 6085 because there was a small barrier to stop knights falling off but in this set this doesn't exist.
As for the small prison, I don't mind getting one in every castle set. After all, if this were to be used as a city gate, there could be any number of thieves or spies that would need to be captured and imprisoned. It also increases the playability, especially if this was the first set you got.
Overall I think the set is good, but not as good as it could be. There are some design flaws and the figs are the wrong colours, as previously mentioned. Furthermore, because the walls are black, there is no chance of a role reversal as in 6061 or 6062. The Black Knights have to own the wall. It's a pity that TLC didn't make more black modules so that a more extensive castle could be built, possibly with more than one faction being black.
Sorry if that's abit long winded - it's my 1st post!
Happy New Year!