I can’t comment of the machine you bought, but I’ve restored a few PT260 machines. The PT is the smallest of the Sedgwick range of planner thicknesser’s, it has the same robust solid cast iron construction of all the important bits with only the base being a fabrication. It has only one motor that drives both the spindle and feed rollers. All the other machines in their range have two motors and a gear box reduction for the feed rollers. All PT’s should be left in one position and not moved, they settle and the setting moves a little, typically you would need to adjust it after a month of three after which it should remain stable. If you move them around, irrespective of make, they won’t like you for it.
The noise of the machine is primarily driven by the spindle / cutter arrangement in it. So machines with the same form of cutter (Standard knife, Tersa, Spiral etc) will have very similar noise levels. They all have one or two motors and perhaps a gear box, which at a decent size of machine will be the same type, induction. Sedgwick used to use only Brook Crompton motors (they don’t make fraction HP motors any more) which are very good quality motors that are really well balanced. The main issue we have found is that the pulleys aren’t necessarily as well balanced. Doesn’t really affect noise, but adds a minuscule amount of additional vibration. Again something common to other machines as they are jelly bean parts.
Setting up a Sedgwick to work properly isn’t too difficult, but you do need a clock and a good straight edge if you’ve taken it apart.
The fence is a proper cast iron webbed arrangement, wonderfully stiff. Most people set them to 90 degrees and then they don’t usually change it! It stays set. Planning thickness is a little rudimentary, with only a simple manual scale. However, most stuff is surfaced and then thicknesses so, accuracy of the surfaces isn’t too critical. The thicknesser is again a scale, but the thicknesser table sits on a very robust large column, they are as accurate as they were setup (parallel to the spindle / how accurate the knives have been set) A simple digital readout is one thing that would certainly be a big improvement, and I don’t know why Sedgwick didn’t add this to their machines, rather than having it as an option.
We are restoring an old Sedgwick MB at the moment that we writing a thread on. This is a very old machine and the only things that so far appear to have worn are the chain and sprockets which is expected for any chain drive and the bushes / bearings. This is to be expected and typical maintenance.
The older dust chutes weren’t as effective as the newer version. But they do need a lot of airflow.
For the price bracket there isn’t in my opinion much that can better a Sedgwick. They are a very solid accurate machine.
Clearly personal preference is a very important determination on what works for an individual, a poor experience is a poor experience. The Wadkin and Dominion machines are definitely more robustly made, but they also sat in a different price bracket when new. I would say that Secgwick are appropriate machines for a small shops, where they are looked after rather than a large shop where they have to withstand inexperienced / don’t care gorilla’s abusing them.
The chisel capacity of the Sedgwick is 1” in softwood, and 3/4” in hardwood, which is identical to the Startrite. Looking at the Startrite machine it appears to be carbon copy of the Sedgwick. The largest difference I can see from the manuals is that the Sedgwick uses a weight to return the Morticer head where as the Startrite uses a pneumatic spring.
the good thing is that parts are interchangeable so you can get spares for almost any vintage. 
