I have the X-tools one large spanner one and it's done me well so far. (all though it was cheaper when I bought it)
Though I have use another a friend had looks similar to this with gnarly bits at the side
It was great to use but needed the arms off. Worth it though just for the ease of using the tension bolt by hand to get it just right. If I had the money I'd have that as well.
I use a 'sh*te' 'kenli' branded one (spanner) which isnt full round but about 75% which means i can slot it over the axle while the cranks are still on and thus use it as an extractor too.
I didnt see fluffychickens pictures the first time, hmm.
But yeah thats what i do although in hindsight (as in a few minutes ago) i gave some thought to putting pressure on the bearings BUT i guess the load is evenly spread and what not and it hasnt affected my bb's at all.
Surprised this isnt common practice!
Its a bit 'faffy' to take spanner off/on/off but im sure its no more than using an extractor and then a bb tool also.
to be fair to take HTII cranks off you just undo 2 allen bolts (for most like XT/SLX Ultegra I've seen, XTR might be different) and the tension bolt and that it, not extractor is needed.
Yeah your right for all the shimano ones i have seen. My raceface cranks have the extraction bolt designed into them but its handy for my truvativ hussefelts.
The Park tool does it for me where others have failed and applies force in line with the bearing. A tool which fully encircles the bearing housing is better. The ones which only go three quarters around can "spring" apart under extreme force.