i say get the controller. it could save lots of money and work too. if your heater gets stuck on(they do often) the controller would pay for itself. being able to see your ph swings with out testing at all hours is a great thing. right off the bat you could set it up to control your lighting cycles, wavemaking, ph and temp monitor, heater control, not to mention having everything on one unit=easy water changes you dont have to look for "what plug does this belongs too". have it turn on the lights if ph drops too low at night or turn fans on if it gets too hot. the other uses of other functions can be used as your needs/knowledge grows.
spending the money on the controller will not keep things alive but can prevent sudden death or other issues(ph swings, heaters with minds of there own). forget buying a bunch of timers, individual temp controllers, individual ph monitors like pinpoint(no data reviews), if its in the budget, get the controller, JMO though.
i personaly have the octopus 3000 to be used on my big tank and Aqau Jr for my other tanks. the Aqua Jr is comparable to the rk2 and i love it
i went with the Aqua Jr for its alarm system and computer hookup control and seasonal variations of lighting and flow patterns. but the RK2 is a great little unit also, like the menu set up on the RK2 a little more.