We haven't found Splendor to be a particularly deep game, but depending on the cards that come out, various strategies are very viable. We've had winners who went primarily for the big cards (note the 10 chip stash limit), we've had winners who built an engine (multiple level one cards, a few level two cards, and maybe one level three card), and we've had winners who just grabbed the right cards at minimal cost to get three nobles and a couple scoring cards. What's always important is keeping in mind the 15-point score that ends the game -- that's only three high-point-value cards, so wasting actions taking cheap or free "engine-building" cards late in the game should be avoided.
Unfortunately, the random card draws can be big windfall bonuses for some players and significantly harm others. Reserving cards somewhat mitigates this, but it's usually not worth throwing yourself on that grenade in a four-player game. It's a fast game, so in two sessions we've played about six times. It's a game that's largely lost its luster for me, but others may still want to give it a few more tries.
