Crystals for gear is ONLY better (looking purely at efficiency) if you're refreshing beyond the 50/50. Using only the 50/50 refresh, all gear is cheaper in pure crystal cost, if you farm it. Of course, if you have 1400 crystals lying around and a stun cuff pops up... well... even so, crystals are best spent on 50/50 regular energy, after that on gear or 100/100 cantina energy, or the 100 crystal energy refreshes, depending on what you need most, from an efficiency pov.
Energy refreshes don't only give you gear and shards. They also give you XP, an important resource to let you progress faster: the faster you level, the faster you unlock other aspects of the game, which allow you to stay ahead of the curve. If there's any advice I wish I had gotten sooner, it's to always buy the 50/50 energy refreshes.
Re Boba vs QGJ: Boba all the way. QGJ is the second toon you should farm from cantina shipments, but Boba is (1) incredibly useful in all aspects of the game except raids, (2) a scoundrel and (3) a good leader (see below). QGJ is more useful in raids, but by the time doing anything other than tagging becomes important in raids, you'll have had enough time to farm 2 toons.
On the topic of tagging, it is important that you farm at least one toon all the way to 7* asap. That allows you to tag in a heroic raid, which will get you guild credit, regular credit and raid gear. Even if you think furnaces and droid callers are useless and what you really want right now are those pesky blue hairdryers... trust me, you will want furnaces and droid callers soon enough, while having millions of surplus blue hairdryers (and a shortage of purple ones).
Re Empire for newbies: I love my empire team. But for low DS battles it's really not necessary. That said, you do want a decent dark side team, and TFP is a good toon to farm (after Lando) who stays relevant late game (raids and specific arena comps). Royal Guard is also good, and worth slow farming from hard nodes. Other Empire available at low levels, Tarkin, Veers, Snow, Storm and Magmatrooper are all bad BUT there is a rework incoming. The Veers rework so far looks a bit underwhelming, but if the troopers are made amazing, they might make a good Empire package. The other (currently) good Empire toons become availabe later: Vader, Emperor Palpatine, Shoretrooper, Death Trooper and Director Krennic are only available later (and should be farmed). Tarkin is a bit of a special case: as a toon he's mediocre. As a fleet commander he's worth farming (although I personally prefer Ackbar). You will unlock a free 4* Tarkin in one of the ship events. So definitely don't unlock him from arena before then (same goes for Ackbar and Mace). At level 82 you will need 5 4* dark side ships, and 8 5* ships of any kind in order to unlock zeta challenges (an important resource at endgame) as well as Tarkin's Executrix. These challenges are quite tough, so it's worth dedicating at least some farm to Tarkin (and other dark side pilots), but imho it should not be prioritized.
Final piece of advice: leader abilities only work if the character is in the leader position. It seems obvious, but I have seen so many Nightsister Initiate or Jedi Consular lead teams that it is worth mentioning. This means only one leader ability will be active per team (two when you can invite an ally: you also get the ally's leader ability). An excellent leader for an early game team is Boba. His leader skill is not faction specific (although he gives bounty hunters extra bonuses). This is yet another reason to farm him first. Lando is a great leader too, but only gives his bonuses to rebels and scoundrels, so only use this if you have a good number of them. Chewbacca has a bad leader ability, but he has the only one you're guaranteed to start with. Try to switch him for someone else (Boba) as soon as you can. Other decent leaders available early: Ackbar (rebels only), Phasma (works with all, best with first order), Rex (especially for clones, but often used for all, particularly to boost Rex himself) and Qui Gon Jin (jedi only). Using a leader ability for a specific faction doesn't mean you should only use that faction in your team. But it does mean that the less of that faction you use, the less use you are making of the leadership ability (and thus usually, the less your team synergizes: there are some great out-of-faction synergies, but they are generally less obvious).
Regarding packs: some of the money packs are worth it, but it always depends on what you want. I regret not buying the Nihilus one, but especially as a new player it's very hard to know which ones are worthwhile and which ones aren't. At first, I would probably refrain from buying any packs and buy crystals instead if you want to spend money. And then don't spend your crystals on packs, but on refreshes, gear and the odd targeted shard purchase from the shop. For the other packs that pop up with every event, keep an eye on the forum, which always has people complaining or cheering (lets face it, complaining) about the packs.
