Of the Silkys I've tried....
I've tried quite a few handsaws (Silky, Jameson, ARS, Fanno, Fiskers and Felco. Maybe some others.) I will never bother with anything besides Silky again.
I was issued a Zubat at work, and it was my first Silky. I'd still recommend it as a best "all around" type hand saw. I'm a pest tech, and when there wasn't pest work to do, I got sent out on a lot of ornamental prunes that most of the climbers didn't want to do. I never felt that the cuts I made with the Zubat were too rough. Occasionally, the depth of the blade made it hard to get into the tight crotches of a small crab apple or something, but I never felt like I couldn't make the cuts I needed to. The Zubat also does fine removing 4" or even larger limbs (in most species). Lastly, I really like the handle on the Zubat. It has a nice heft and a generally hand-filling, grippy feel.
I got a great deal on a Sugoi when I was looking for a little bit bigger saw to take up in the tree for cutting bigger limbs on large prunes or removals. I was trying to decide between a Sugoi and an Ibuki. Came down to the deal I found. The Sugoi is definitely faster through bigger cuts than the Zubat. That being said, I am not (as yet) totally enamored of it. Where I loved the grip of the Zubat, the Sugoi is more flexible, has a bunch of ridges, an aggressive butt hook and is generally more squared-off. If it fits your hand, you can probably really reef on it more than the Zubat, but I personally don't really like how it feels in my hand. It's possible that I'd like it better if it was my first handsaw, and I wasn't more used to the Zubat. A few more (maybe personal/picky) things I notice with the Sugoi: The tip "vine cutter" (or whatever it is they call that thing) seems to get in the way when I am trying to do a single quick pull to take a small-ish branch off in a single stroke, or to pull fast through the bottom of a cut to drop off the branch. I notice that Silky doesn't have the tip thing on the larger version of the Sugoi they released. Also, for some reason, my Sugoi seems to get caught up alot when I slide it back into the scabbard. Actually dropped it out of the tree once because of that. Not a big thing, but it is kind of annoying.
I finally got a chance to handle an Ibuki the other day, but not to cut with it. It felt like the big brother of the Zubat. The handle is a bit fatter, but has the same rubber and heft of the Zubat. Recognizing that I haven't cut with it yet, I think if I could do it again, I'd trade my Sugoi for an Ibuki, based on the way it feels. It's a Silky. I know it will cut.
I feel like I should mention the Hayauchi pole saw. I love it. It's heavy, but it really does allow you to make quality cuts, quickly, at 25 feet in the air. It lets me cut things from the ground that I probably would want to climb up for, were I using a lesser pole saw.