I've got a 4*60 with a YS .91FZ mounted up front which gives the plane the power of a 1.20 size motor. This combination allows me to take off and go directly vertical with no hesitation until I decide that is high enough and level off. My 4*60 was a kit which allowed me to modify the plane more than an arf could be (well easily anyway). Extra support, bracing, 1" extra on rudder and elevator, dual elevator servos, pull-pull rudder system, front hatch compartment, Modified rudder on top to act like an "Extra 300" rudder acts with the counter support on top while flying and a few other mods that were done. Hovering is no problem what so ever with this YS engine. Knife edging is very easily accomplished. Just remember that the 4*60 is not a pylon racer, so be easy with the throttle in a dive if you use an over powered motor, but the vertical performance is outstanding.

I would suggest the following motors in order of preference..
YS. 91FZ
YS 1.10FZ (more costly than the .91FZ)
Saito 1.20
Saito 100
Saito .91
OS 1.20
OS .91 w/pump
OS .91

All 3 brands listed are very good motors and any one of these motors above will fly the 4*60 with ease and much fun. Vertical performance would be great also, but landings could still be made at a snails pace with full flaps deployed.

My thoughts on the matter.

Enjoy your 4*60,
DTB