Im a lvl 20 R/Mo and i have to say, its not a bad mix at all, Monk seem to work out with all classes in the game.
But! Beeing a R/Mo is most usefull in the early hours of the character, as you move towards Lions Arch you will use less and less Monk skills.
Hey, the only skill im actually using for a Monk is Rebirth atm.
I do not wish to change my mix, since i like beeing able to ressurect many times, and it will be very helpfull when you play PvE, in PvP altho, i dont know if you really get the time to use any of the Monk Potential when you are playing as a ranger.
I could always define it as this, Ranger skills rule, but Rangers doesnt have the amounts of energy needed for them (unless you really want to go with that horrible looking Druid Armor set).
Im a lvl 20 R/Mo, and i only use Rebirth from my monk profession.
I am currently using 3 Diffrent bows,
1 (short bow) with 10% Penetrating, +28 Health and +10% dmg while hexed
1 (ascalon bow) with +15%DMG when HP is above 50%, Energy String (+1 Energy / hit, -1 Regen) *Also note, -1 regen makes you gain 2 regen instead of 3*
1 (storm bow) with +10%DMG when hp is above 50%, Cold Damage and +23 Health.
Reason why i listed these, The Energy one, if you plan to go R/Mo, you cant live without it, Barrage + Tigers Fury + Energy Stealing = ALOT of energy (as long as there is atleast 2 foe's)
With that you might be able to get the full potential out of your R/Mo, if you create one.
I also want to note, these are my 2 cent, i dont want any flaming/flooding/comments about my own theories in the game.
These are my theories, and they wont change, even if you try to convince me that it stinks/suxx.