When buying effects, remember that the sound of the effect when used with a loud tube amp is better and rounder than the sound of the effect in isolation. Placing time-based effects before distortion or before power tube saturation sounds muddy. The safest placement for time-based effects is after the mic'd guitar speaker. Connecting a guitar preamp unit directly to the mixer is safe, easy, and fake-sounding. Rock listeners want to hear the real, physical tone of a stressed speaker wrestling with power tubes.
Effects sound better when combined optimally with a tube amp than when used directly into the mixer.
You can connect effects and amps in many ways. But the default, optimal way of connecting them in the recording studio is to place time-based effects after, rather than before, any heavily overdriven stage. This prevents beats and preserves a clear Basic Tone. When using a saturated power tube tone, reverb and echo are clearer when placed after the mic'd speaker, rather than before the power tubes. When playing clean, the order of effects and amps is more flexible.