TidyCal is nice, and it does a LOT. That said, it needs a little work.

1. For some reason, you're expected to set the meeting duration not only under the "Duration" setting, which is obvious, but also under "available time slot interval" under "advanced settings." If you don't, you'll end up with a mismatch between the advertised duration and the available meeting times (say, you're advertising a 20-minute meeting, but all your slots are in 15-minute increments). This is totally unintuitive and bizarre, and should be combined into a single setting. Why you're expected to do this twice, and in a second place that's not obvious, is beyond me.

I hope this is the only setting that works this way, but if there's one, it's likely there's more than one.

2. The online help is often not at all helpful. For instance, the help for that second setting above--which you might wonder about when you discover that you have to set the second setting (just what the heck IS the available time slot interval?), says, "Defines the interval of available time slots on the booking page." Well, that doesn't clear things up at all, does it? Definitions shouldn't ever re-use the term being defined, folks, because that doesn't actually clarify anything.

A lot of the entries are like this.

3. According to the roadmap, it's possible to set an appointment yourself for a client. I can't see any way to do this except to go into the booking page and pretend to be the client--and maybe that's exactly it. That doesn't show me the booking in the client's time zone, though--just mine. So I'm not sure what the client will receive in their confirmation email, or if I'm getting the time right for them. There needs to be a way to do this that shows both times side by side to ensure accuracy. After all, dealing with time zones is a big part of why we need a service like TidyCal, right?

I appreciate that TidyCal has something of a minimalist interface, but it may be a bit too minimalist--if there's another way to do this, I haven't been able to find it.

4. The support I received when I contacted AppSumo for my issue with the problem described in item #1 was the worst I've ever encountered with this company. The rep fixed it for me without explaining what she did, or that there were two duration settings, not just one, and expected me to go figure out what she'd done on my own. Thus began a frustrating back-and-forth that could have been avoided if she'd just been forthright and thorough in the first place. I was, and still am, stunned by it, considering how good AppSumo's support usually is.

I'm not giving up on TidyCal--at least not yet--because it's clearly a pretty robust system, but this hasn't been an auspicious start. I'm happy to revise this review (assuming that's possible!) if these issues are addressed.