Little correction: you get a 12 hour shield when either the TH is destroyed or when you lose with between 40%-90% destruction (16 hours for 90% and up).
I would stay that it is a matter of preference. Some players feel they are better with trophy bases, others, not.
Personally, I don't think trophy bases are worth trying unless you are at TH10 and already maxed out most of your defensive buildings (if not all).
If your goal is to get trophies to get into a higher league (and since you are at TH7) and you have a decent amount of time to make attacks, I would advise using a farming base and try not to keep loot in your village. As a TH9, if I find a farming base with decent loot, I can assure you I would not let this village pass with a simple snipe :) (unless I am in a mood to give 'free' shields).
I cannot say for all the players out there, but my experience is that in Gold Leagues and below, players tend to go in regardless of base if there is decent loot. In Crystal and Master, they tend to snipe and move on instead of going in and shoot for the loot. The reason is that people in this league are often shooting for the achievements and are more concerned about trophies (and getting trophies quickly!) and less about loot, and because there is mostly well upgraded TH9 and TH10.
At the moment (we don't know if supercell is launching TH11 soon), TH10 is the best TH level to use a trophy base and push to the legend league.