I'm glad I stumbled my way into this thread, I'll definitely be trying to pick up one of these tools in the near future!
To be honest, one of the main stumbling blocks I have right now is just trying to decide whether I want a rectangular tool with or without one of those finger cutouts. I think I'm just having trouble mentally picturing whether the way I'd grip a dab tool would be helped or not by having that little cutout there. If anyone that already owns one of those tools could post a pic of it in their hand, I think that'd probably help me decide, as I've pretty much settled on one of the rectangular tools with a spear-tip, just have to decide whether I want that notch or not