Re: How good are the TC Electronic Nova Repeaters
They're pretty good. I have one, and it can produce some really nice, lush, warm delay tones. Also has vibrato and chorus which can be dialed in, and although they aren't customizable at all aside from the level/mix, they too sound quite nice. It can operate at either line level or instrument level (has different input jacks for each)
really the only problem I have with it is that it cannot run off a daisy chained 9V power supply without adding some noise (specifically the noise of the tempo indicator LED blinking on and off) to the signal chain.
I haven't tried it with an isolated power supply unit like a PedalPower or a DC Brick, but it might fare better with those.
Otherwise, it's a simple to use, very good sounding unit.