My putter search took a few years, as I could never find one that felt heavy enough for my stroke on the slower green speeds. I ended up going from a light-weight traditional blade putter to a mallet, with adjustable weights (the Ping iWi).
Then when I joined a private club, where the green speeds were noticeably quicker, the heavier putter worked even better, which surprised me. I thought I would struggle with the adjustment but it only enhanced my feel on quicker greens.
So really, once I found what I felt was my Holy Grail on the greens, I stopped looking. There's nothing on the market all these years later that I could possibly have more confidence in. Just because I had a bad day on the greens doesn't mean my putter has suddenly stopped working. It just means that my stroke became wishy-washy. And no putter will fix that. If a bad round turns into a bad week, oh well. Still no need to panic. Beyond that, then I seriously need to get on a practice green and work on getting my stroke back.