Cant speak for Control.
I know it hugs the Bosses ass and spams the hell out of it.
I can Imagine that it works well for a comforting playstyle and as mentioned books are cheap too.
TTH swiftness is propably a bit more stressful at first since you have to cycle through your skills very fast. Also conviction judgement is a must if that were to be a hinderence.
I main control glaivier and, in my opinion atleast, its one of these cases of easy to play hard to master(full potential). She is incredible forgiving in some scenarious since she is fast and has overall low cds on abilties. Conviction/judgement is also mandatory.
Overall a very good play flow 
Only downside is big numbers. If you want big numbers, control glaivier is a no no.
I don’t really care about big numbers atm (aiming for Aeromancer soon as main and maybe slayer)
since for 1500 lvl 7 gems are more than enough and books will be a longer term investment either way id say go for swift pet summoner, it has very high uptime very easily, does good damage and its hitmaster, also has massive utility for destruction / stagger and 2x synergy (mana regen and def shred)
taijutsu scrapper would be the next best choice but is also back attack, control glaivier is back attack and has massive mana issues if you are playing with a mediocre support and even with a good one you have to be managing your rotation to some degree
Go for a transformation class, scouter or shadowhunter they require little investment
Dont go gunslinger if u want to progress or learn the new raids.
If u want easy to play classes go for
Blue GL
Gravity Destroyer
A good comfy class that everyone sleeps on and is pretty cheap (at least it was when I was playing)? Sharpshooter.
as person who has a 1545 sharpshooter would not go for that you get gatekept pretty hard and the class needs a complete rework to feel fun to play
I have an 1430 GT Desto and i am going to push him instead
CO is still very expensive though in terms of Tripods. And yes 4-5 makes a huge difference.
Also while being non positional calling it a “hitmaster” class is a bit misleading since you usually dont run hitmaster. Its okayish to do but your Awakening is not affected. And the Dude packs quite a punch and you get him out often.
Its an option and you could easily apply as a Prokel Killer.
FI Wardancer:
Very fast and mobile, does not have to back attack, 20% damage reduction with max tripod on energy combustion, great synergies (+18% crit, 8% atk speed, 16% movement speed).
Gunlancer:
Slow but very high shield uptime with push immunity. Great synergies.
Downside for both: need many tripods to be relevant.
I was looking at FI Wardancer though than control glavier
gunlancer!
Right now down to ESO 2/3 spender Wardancer … have gunlancer/desto (pushing desto to 1445 soon after artist)
Any class with a recommend stats of 50:50 on Swiftness would do it.
You won’t be too slow to dodge , your skill not cooldown fast to be a piano class and your dmg is still enough to get things done.
Control better less rotation and more Swift
Sorry tried control and not my taste and not wanted so decided to go for Wardancer
Legacy scouter.
Tried scouter nothanx