I use HCl + H2O2. With FeCl there were problems with family life - my wife do not like yellow points everywhere - especially on my new trousers;-). And you could believe me it is impossible to wash off !!!
HCl is better for etch because of room temperature. With a small dose of experience, (and a medium dropper for flush) you could controll speed of etching of different areas. Remember that oxides slow down etch processes, to speed up process you have to mix whole solution. By the other hand the places with closer tracks are etched faster, and empty places are etched slower. So to avoid over etch I am always flushing with dropper empty places of board, and then mix and etch places with tracks. So the most demanding areas are etched last, and over etches are minimal !!!
Additionally - except of good results of etch, use of dropper is very fun - before I've used dropper I didn't like the first stages of etching - before results could be seen. Now it is really fun.
Btw I use plastic, "single use" dropper of about 5 ccm volume, but I think a small pump could be better ??
I have tried some methods - air pumps, bubble, spraying etc. but in my oppinion manual etch is the best - of course for "home" scale technology.
regards
KamW