The Octagon 20DX and 40DX has been around for many years and 'back in the day' on the old pekin bantams forum, most of the breeders were using them in anger. I used one for 5? years I think and it never once let me down. Well built and provided good results.
The negative point was it was difficult to clean under the lid - the electronics / fan had a plastic guard around it that would suck up fluff during a hatch and get messy. After a couple of years, I started using a separate hatcher (still use it now) so I can add eggs to the incy at different times and mix chicken / duck eggs, taking them out for the high humidity part at the end, hatching and cleaning a Brinsea Polyhatch. The rest of the Octagon was very easy to clean.
The RCOM is easy to operate - press and hold 'Chicken' walk away - top up water every other day, if you forget, it beeps at you! I have found it easy to clean - it comes apart but you still have potential for the fan grill to suck up some fluff into the electronics but with care cleaning (I do keep a can of compressed air for blasting these things from time to time), this isn't a problem. Again though, I rarely use this to hatch.
The Suro was the easiest to clean - the electonics in the lid can be unscrewed and cleaned (again with care... no water!).
Have a look at them and see what you think.
I have used Flyte so Fancy for years (fantastic customer service) and Chickenhouse man a few times. I would try to buy from someone who is reliable because incubators can and do break down from time to time. Interhatch who distribute RCOM in the UK have been amazing - I could phone them up, speak to a techy guy and discuss problems - they have sent parts in the post next day. When I tested the SURO, they sent me a loan unit for 6 months.
Hope this helps and do let us know what you finally go for!