My thoughts on the ES125 and the new ETS125, they are not as smooth as the ETS150 sanders. However, once you dial them in, the 125's work well. You do need to play with the speed and suction with each particular grit paper to get it just right. But ask yourself dose it need to be as smooth as the larger sanders? I say no, here's why. The 125's are used mainly for smaller surfaces, like faceframes. How flat do they need to be? Now with larger surfaces, say a panel or a table top, dead flat is what you are after. This is were the ETS150's and even more so the RS2E excel. This is because of their exceptionally smooth, flat orbits. I'm not suggesting the 125's can't product flat surfaces.
They can, it just takes a little more effort, to dial them in. The bottom line, the ETS 150 can't do the ES/ETS 125's job any better. Meaning, the bigger, smoother sander won't make a faceframe's finish much better. My ES 125 sees a lot of work, I just make sure I use for the jobs it is intended for.
Keep two things in mind:
My advice is always free.
And, you get what you pay for.
