This thread is really interesting to me because I couldn't find a really good comparison between the Seagull Pro and the Scuba S1 when I was deciding which to buy, so I bought both (SG Pro was $399 at Home Depot and Scuba was $499 at Costco) with the intention of returning one. Been using them for a few weeks now, and I am struggling to decide which to keep.
I prefer the design of the Seagull Pro - vents drive water upward and not on a backward angle like the Scuba (which sometimes disturbs debris on the bottom and then it doesn't get picked up on the next pass because it's still up in the water). The basket on the SG Pro is way easier to clean because the lid comes fully off. However, it only cleans for 2hr and 15min lately, despite being at full charge, and I think it has no time/strength to get up the walls on floor+wall mode because it doesn't do it first. So I've been doing only one or the other.
Scuba seems like it has a longer battery life, but I'm measuring for sure this week. The "drop it and leave it for a week" method worked out okay while I was out of town, and it's auto mode prioritizes walls first then floor so it really cleans the water line. Much to keep considering but I gotta take one back soon...