I've left and returned several times since 2011. I like Tiny Core best of any linux I've used. I use it as my main machine for software development whenever possible. The longest stretches were for a year during 2012-2013, and for the last 4 months until now.
Tiny Core has some kickass advantages, mainly that it's not a bloated pile of festering crap, yet it's still readily and highly usable. It's package install system is the easiest, fastest, and most impervious to damage of any I know. See htop in 1 page! No systemd! Doesn't eat up all your resources. Good learning experience.
Now disadvantages: less hardware support (e.g., for random wifi cards). Maybe dCore solves this, but I run big ram apps (e.g., R) and need 64-bit, and there's no dCore for CorePure64 AFAIK. When I successfully install a large, complex package, I sometimes find it goes easier to install to /usr or /usr/local instead of to ~/.local, then find it easier to just not restart for a long time, then, when I do, I just sudo make install it again instead of making a tcz. I don't think this is a good practice, but only mention it to say that if the route to making a tcz was as easy as possible, I would contribute more, and I suspect others would, too.
Where did I go? Sometimes installing and setting up necessary software takes more time and learning than I have available, and I have to fall back to e.g., Ubuntu server until my workload lightens up.
Don't worry, I'll be back soon