Audible differences between low and high end analog mixers

So I have a bunch of vintage synthesizers, and some guitars. I only really ever need to record one thing at a time and my ADC only has two input channels.

I would like to multiplex all my inputs through an analog mixer so I can just leave everything connected (4 mono + 6 stereo) instead of having to constantly unplug and plug things into the A/D converter. The ability to route the outputs of certain channels through the same fx and outboard gear (synths through reverb units, guitars through pedals, all going through some coloring units) would be great for less plugging and unplugging as well. Occasionally I might layer up two or more separate sounds, but the rest of the work is done ITB.

I don't need a mixer with tonnes of A/D converters and inserts, just a simple purely analog summing unit. For these purposes is there any benefit to an expensive desk console vs a typical cheaper analog mixer used for live sound?