Just passed the 150k mile mark & the AW 30/40 is a bit hesitant to upshift first thing in the morning. Seems like a good time to change the fluid. Any advice on the following would be great:

Should I:
1)have the fluid changed at an oil-change place - they use the machine that promises to flush out all the old fluid.
--or--
2) Do it myself, following the instructions here on Brickboard about draining from the transmission cooler lines, filling with the long funnel, etc.

Other than cost, is there any reason NOT to use the power-flushing service?

next question is about changing the filter in the pan. Is it worth the trouble? It's not so much the filter I'm concerned about, but all the complications on the orange sealant putty, and worries about shearing a bolt (which happened to someone here). Changing the fluid myself is one thing. Dealing with the whole pan, scraping off the old orange goop, setting a new Toyota/Lexus gasket, and worse, introducing the possibility of new leaks from a transmission that does not leak right now.

I'm sure that replacing the old fluid with new synthetic will make a difference. My question is whether changing the filter will make the car that much better than just changing the fluid.