This problem was urgent: guest bathroom toilet (not used for days) spontaneously overflowed and flooded the basement after a shower elsewhere in the house. (Luckily the flood water was clean!). Preliminary diagnosis -- plugged sewer line. And more guests arriving later the same day!
I called Red Seal before 8 am, and by 8:30 was talking to Alex, the plumber who would be doing the work. By 9:45 Alex was on site and at work.
This house was not easy to work on: nearly 100 years old, ancient pipes, prior renos with botched plumbing, barely accessible sump to explore, numerous steps to haul equipment up and down, and throughout it all Alex was pleasant, explained clearly what he was doing, and was patient with questions. It was obvious he was knowledgeable and experienced, and that he enjoyed his work and solving challenging problems.
Best of all, he found the blockage (roots growing into the sewer line), and with some effort managed to clear it! He got us through this emergency and made suggestions for future work we might consider.
I would have no hesitation to have Alex back for any plumbing or drainage issue. If only all emergencies could turn out so well!