FWIW, I run an Ultegra 52-42-30
That's a good combination, and will shift better between the more-commonly used middle and outer rings than 39-52 will, due to the smaller difference. You'll be able to spend most of your time in the middle ring.
Triples get criticised a lot for not shifting well; but the poor shifting is the fault of the mechanic who set it up, not the triple itself. It looks really simple, but it's not, and even a lot of so-called "professional" bike-shop mechanics get it wrong. Presumably the tiny ring gets used very little, but it's important when needed. Outside of that, the shifting between the middle and outer rings is no different from that of a double-- nothing is any more complex, etc.-- but the 30-42-52 has the advantage
over a 39-52 or a 34-50 double in that the jump is smaller. Front shifts on my triple take one half of a turn of the crank, which at a good cadence is less than half a second, and I never drop the chain. What more could be desired?
A good adjustment requires that the front derailleur be low enough that it nearly touches the big ring's teeth on the way by. A few derailleurs work better with about a sixteenth of an inch clearance or slightly more, but definitely under an eighth. I see this violated frequently. The other thing that is missed all the time is that the rear tip of the cage should be rotated out slightly farther than the front, such that if you unscrew the limit screw and pull the cable far enough, the crank arm will touch the rear tip of the cage as it goes by, not the side.