We have the same Kalven tree as Rosella's, and find it great. It also packs in quite a lot of tree for a comparatively small footprint, which is useful if space is an issue, as in my one bedroomed flat!
We also have the Colossus from Russell Hardy i (hopefully attached - not tried attachments before!) . Again, small footprint, large tree, sturdy, and very well used.
Would definitely endorse both makers! Plus you get some say in the colour of the tree etc in both cases.