The tree of transformation is extremely useful particularly with bees.
Wanted to settle in a desert to use Ruby to replace diamond in E crystals?
Now you want to do bees and are kinda screwed unless you go miles from home to find a biome?
The Tree of transformation got ya covered.
The rest of em I haven't used much though, considering how much tech you need to safely explore enough to get a reasonable number if trees, by that point they may be nearly obselete.
The mining tree above a hollow hills sounds like a good idea, but then again once you can fly, hollow hills become 80% less dangerous.
In 1.5 skeletons mean that you may need some small walls when mining veins, but in general it's safer.
The best thing to have in a hollow hill IMO is a creeper spawner.
They blow up, and give you space, by killing the surrounding mobs.
A skeleton spawner on the other hand...
Get rid of it immediately.
I just cleared out a hollow hill today in some DC gear, Armour with flight, repair, speed, damage, fortune etc, and a combination of a grinding smelt pick for metals, a fortune 4 pick, and a speed 5 unbreaking 3 pick for mass breakage.
Went in looking for gold, having only 7 left.
Came out with 2 stacks, as well as TONS of redstone, and iron, and a good bit of copper tin silver and lead, and bucket loads of coal.
Also found 2 uncrafting tables.
And all this was easily done.
But yet, in the time taken to find a miners tree and run it, I would have had it cleared out.
So all in all- Transformation Tree useful, the rest of them less so.