My guess as to what was meant -
1. One thing to consider with T-Maps is risk/reward.
Fel has the "better" loot, but is still limited to the traditional loot (human gear). There's also the possibility of getting a map in an unfortunate place, that you have to store and wait for it to reset, hopefully in a better place. (Doing a map located between the Yew Animal Trainers and the Moongate in Fel was scary enough on LA - god forbid you had one within sight of the Fel Yew Gate on Atlantic -though if you lived long enough to dig it, the guardian spawn might be an interesting surprise for the residents)
Ter Mur Maps have Gargoyle loot in them, which of course have better resists. So, if you're looking for Garg gear, Ter Mur is better simply because you will have better suits than if you did a Tram or Fel map and modified the stuff for race.
Ilshenar might have elven items in it. Been a while since I did one. Tokuno, of course, is mostly SE gear.
2. Because of the new tamables, Tram/Fel maps have higher costs when for sale. So that that it's possibly cheaper in the long run to get them from others, though getting the right item might cancel out all that expense (or make the gap wider).
3. Ter Mur maps are FAR easier than any of the others, at that level. Ilshenar, somewhere in the middle (and a lot of it depends on location - I've had two level 6 or 7 maps INSIDE the Valor Champion Spawn area, which means that you're getting swarmed by small stuff and the occasional Dragon/Greater Dragon/Paragon of either, in addition to the guardian spawn). The three hardest T-map areas for level 6-7 are Tokuno (hardest - as much for the spawn as the local monsters, ninja and ronins jumping in), Fel and Tram, in that order. If you run into time limits, the ability do 3-4 maps in the time you'd do 2 in Fel is enticing.
