Pluses for Karin & Charoen is that they are "hotels" as a Farang would describe one - so.. price includes breakfast (of dubious quality I am informed, but never tried) & have lifts to multiple floors.
The Silver Reef does not have a lift, but is only 2 floors anyway. They used to do a very decent breakfast which you could have as an 'add on' to price. The owners (well when I knew them) were both extremely pleasant people who spoke fluent English (well as much as a 'Canadian' can do

).
The Ruy Suk & Top Mansion are much the same. No lift to rooms (4 floors in Mansion, not sure about RS) & no breakfast. Both VERY clean but pretty basic in what you get. Some complain that beds are hard - which they are

but that is not a problem to me personally, rather an asset. The reception staff in the Mansion speak very passable English, the owner of RS speaks excellent English.
Although neither serve breakfast (what does someone expect for 350 baht

) that is not an issue. Nobi is right opposite the Mansion & the Clock is just up the road. The RS is (at most) a 10 minute walk away & you have to pass Chern Chim after about 3 minutes who also do a more than passable breakfast.
The Mansion seems to be pretty full nearly all the time, the RS usually seems to manage to find a room
The two hotels are quite large establishments so are probably less of a risk if not having pre-booked.