On RPG.net, Darren MacLennan gives Trail of Cthulhu a 5/5 playtest review. Despite encountering some of the usual roadblocks for players new to GUMSHOE, Darren concludes:
On the other hand, Trail of Cthulhu taught me how to write an investigative adventure, has a ton of useful resources for Call of Cthulhu – and if you’re not married to Call of Cthulhu already, like I am, it’s entirely possible that it’ll work better for you.
He also calls Trail “an ultralight glider,” which is a lovely metaphor of gameplay to shoot for, I think.