When to choose Lantids and how to make the most from them
Lantids will become more attractive to pick, the more of the following are true:


It will be easier to find suitable planets to colonize in games with high player count. So they will be more attractive in a four player game, than in games with fewer players.
During the first or second turn, you will get bonus points for building your Planetary Institute
The round booster giving points for each mine is in play. Lantids should on average have a high number of mines in play already midgame.


Lantids will become less attractive to pick, the more of the following are true:


One of the endgame bonuses is for number of colonized Gaia planets.
One of the endgame bonuses is for number of different planet types colonized.
It's a two- or three-player game.


During the game, you will probably want to:


Get your Planetary Institute on the board early, enabling your special ability to get tech every time you build a mine on another players planet.
Once your Planetary Institute is in play, you should spam mines. This will elevate your income of Iron, and net you a nice boost in tech.
Save one or two mines, though. And be very careful to only build these on planets that have neighbours. Thus you will be able to upgrade them to Trading Stations at the cheap rate, and get the mine back for colonizing new planets later on.


(My personal best score with Lantids at the time of writing this is a mere 148 points. So take my advices for what they are. I'm sure there's more to consider.)