What do you build with her? I've been building brutalizer into tank.
I find it extremely hard to keep her tunnels up against highly coordinated teams, which makes it impossible for me to ult. How do you fix this situation?
You playing top or jungle?
I've only had experience with jungle, and you just have to use as many tunnels as you can in areas that you will need access to (ulting from your fountain with homeguard is legit).
I have been toying with an aoe attack speed build
, 
or 
For added tankiness
or
Against heavy AP
Against heavy AD
Extra Damage
I really like the idea of building tankier while applying on-hit damage to combine with devourer enchantment and sunfire dmg.
I have also been looking at 
if you need more sticking power
This is my personal preference though.
I have been seeing Nightblue3 building her like this:
: (choice fifth item and choice boots)
I see too many people going with which makes no sense for me
The jungle is very tough even for Rek' and 
is much more forgiving and better in terms of farming, catching up, and speed. With Rek you want speed, she has the dmg mid-late game so no point in adding even more dmg which can be risky for the remainder of the gmae
She really works well with because when she pops up from W, she can use Q 3 times in quick sucession thanks to her Ult. Normally, you can use all three within the time they are knocked up, then as soon as the third AA is done, you can use Hydra active and AA again, it's very quick and easy.
She works well with because her abilities can be spammed in fight and out easily.
You don't need anything other than Jungle Item, Hydra, and TF. Rek has a lot of Base HP and as an assassin you don't need to get HP/armor/mr first. She needs
As far as defense goes, and 
With this build if you pop under an ADC or APC anytime during mid-late game, they either blow flash to save themselves or they die. Banshees is much better than spirit visage because the ability to stop one spell is much better than the extra HP or healing factor. Banshee's helps with assassinating much because most champs don't have 2 forms of CC. They need to stop you from popping up underneath them so it's hard in a 1v1 situation. IE, a Vayne split pushing can't kill you because at best she can tumble and dodge your pop up, she can't knock you back due to Banshee. Same goes with most APC.
Be careful of Cass thought, they can stun you will you moving towards them and they can blow your Banshee's easily. Kalista is easy as long as you can predict where she will hop next.
LEBLANC/Zed/FIZZ are the worst. They can kill you easily, faster, and dodge everything with extreme ease.
Personally, I have never liked devourer on her. I've played a game or two with it and I just wasn't satisfied. I've been playing her non-stop since Saturday, she's just so fun! My builds are usually 
Boots are of course situational, I prefer 
if I can swing it but normally go Tabi or Mercs, I feel that SV is core on her, especially with Hydra and her natural healing. Your armor item is situational as well, Randuins is a safe choice but Sunfire works just as well.
for fun I build a Zhonyas last if I'm fed; better burrowed q, armor, and that active for when you engage too soon.
I prefer a more gank-heavy style instead of farm heavy and gank when you feel like it. I push objectives hard with my team, usually getting first drag around..uhh 12 mins? Earlier if we can.
i just go 
into tank items
