A friend of mine had several of the sets under discussion, namely RA17, AR88, early Eddystone dual superhet with half moon dial (model number unknown) and CR100.
In my opinion the Marconi was behind the other three in performance. I actually then sought out an RA17 and an AR88. The AR88 worked (just) but its size and weight meant I never got round to giving the TLC it deserved and I passed it onto another collector who got it up and running.
The RA17 I have till this day and you can see how I house trained it in this thread:
https://www.vintage-radio.net/forum/...d.php?t=105924
I have in the past owned a lesser Eddystone in the form of the 840c, but it wasn't in the same league as the 'half moon' unit. Maybe some Eddyfan would know the model number?