A lot on the site doesn't seem to be working yet. I kept getting the message 'coming soon'.
A waste of time...

Simkl will have a subscription-based model, so at least some things won't be free. Mabye some of the stuff that is free right now will no longer be so when the software heads out of Alpha and Beta phases. Their (cancelled) Kickstarter campaign, for example, included a $99 tier that included 5 years VIP subscription, which the description said would otherwise be a lot more expensive.

That being said, I'm having the same problem as wallpaperflower. For instance, I tried downloading the Alpha scrobbler, but only get a blank page.

@Anamon
you are totally wrong. I spoke with the creator and he said anything users use now is free forever.

@Zoce:
Thank you for the additional information – although, could you provide a link to a source for that?

And, just to be pedantic, that doesn't make me "totally wrong", it doesn't even make me slightly wrong ;) I mentioned that (a) there will be a paid subscription, which still seems to be the plan, and (b) that it might be required for some features that are free right now. I haven't seen any source indicating that, and didn't claim so; just that it's theoretically possible.

@Anamon Hi, I am a developer at Simkl. And let me address some of your concerns.

It's been 3 years since your "it will be paid" comments, and during that time Simkl was the only site among alternatives that did not have a paid option. It was ALWAYS FREE and had ZERO ads for logged in users all these years.

We're building Simkl with the community in mind, and we always listen to what our members want and are making the site and apps around community requests. Feel free to add and vote for your ideas on how we can improve Simkl at http://support.simkl.com/forums/264009-top-ideas-from-the-community and join our community Discord server https://discord.gg/u89XfYn .

We plan to have an additional paid option for supporters only to be able to build new features that require more budget. All the features and apps that are currently available on Simkl will always be free.

[Edited by andrewmasyk, June 13]

I've only been using SIMKL for 4 months now, I believe, and the VIP options, from what Andrew himself has pointed out during my inquiry, will be extra features besides the current general operation of the website.
As for the actual present features, they are too many to count, and many more being added frequently, for example in there few months we got countdown timers, new review improvements, comment/memo changes (from requests), optimizations of the chrome tracker, and the Android/iOS apps, which also got some new features added to them (new sources to check detailed descriptions, such as AniDB).
Andrew and Ishika, the developers of the website and apps are always active on Discord and they solve any issues or wishes that the users whom join the server ask of them. There are channels for reporting bugs and these also get solved in less than 12h.
In other words, I don't know how it was back in 2015, but now, in 2018, SIMKL and the team behind it provide the best tracker for all my entertainment.