I’ve been planning on gettings the Tomb playset for a while now, and it pops up on ebay every so often.
Would y’all consider it a good playset? Worth getting? 
definitely worth getting… it was a super cool playset to have as a kid… plus it displays well now!
I assume we are talking about the LJN playset and not the mini figures one?
It’s definately a cool playset as it captures Mumm-Ra’s throne room quite well. You could easily make a custom cauldron and the 2 other ASOE statues.
The skull chamber itself is cool, but the casket part is quite disapointing. It’s basically a door in the shape of a coffin lid that leads inside the skull (or transformation chamber as it says on the box)
The Chamber is divided into 2 sides (a side for each version of Mumm-Ra) You turn a cog, which turns the transformation chamber around to change between each of your Mumm-Ra figures.
To be honest, I would have sooner not had the transformation chamber feature and had a removable casket that you could place the mummy Mumm-Ra figure in and then place the casket inside the skull just like on the cartoon. I guess if your a customizer you could do this by removing the red door piece and making a custom casket for your Mummy Mumm-Ra figure. A custom made casket would fit nicely in the skulls mouth.
For detailed shots of the tomb playset and further information on it go here:
http://uk.geocities.com/blackiecats/mummratomb.html
It’s from my old site and I believe it has scans of the instructions as well. Hope this helps!
Thanks for all the info Neil!
The one thing I thought it was missing was the cauldron, so I might have a go at making my own, and crowd my Mutants around it.
I used to have the mini figures tomb playset when I was younger, and loved it, it was one of my most used toys at the time! I actually prefer the mini Mummy Mumm-Ra to the large scale one!
If I have the space, I would definitely get one. It isn’t Mumm-ra without his tomb playset, ehehe.
Man, I want that Mumm-ra Box art image!