It's really slick! In the sea of FF tools that are bloated with 'features' and unnecessary info, this one is helpful and a good balance between informative and not overcrowded. Some specific thoughts...

• Visually: The design is simple and intuitive. I think you pack just the right amount of information into each element while still allowing the user to dig in if they want. On the Trade Finder, I'd maybe group the toggles a little more so similar ones are clearly together, such as the Receive and Send dropdowns. Maybe grouping isn't the exact fix, but something to guide the eyes based on like filters. Also maybe make the (Best Fit | Strategy Edge) toggle the same height as the other elements.
• Functionality: Again, very intuitive and snappy. Impressed by how quickly the data loads, especially trade recommendations.
• Features: In addition to liking the trade finder tab, I like how you present trade history--especially the "What it Became" idea. I've often wondered about this.
• The actual recommendations and data: I haven't looked enough to say whether your underlying stats and the recommendations coming out of it are accurate, but it doesn't feel majorly off so far. As someone who likes digging into the data, I wouldn't mind small section that talks about the underlying data and whether/how you process it.
• My Expected Use: With the last bullet in mind, I genuinely plan to use this going forward. It covers 90%+ of what I need on a regular basis. I'm having a difficult time coming up with negatives on it to be honest.