@Trundle Mains! BORK vs Rageblade which is better?

Trundle's ultimate

Initial Magic Damage: 10 / 13.75 / 17.5% (+ 1% per 100 AP) of the target's maximum health Magic Damage Per Second: 2.5 / 3.4 / 4.4% (+ 0.25% per 100 AP) of the target's maximum health

BORK's stats Price: 3400

+40% attack speed +25 attack damage +10% life steal

Passive: Basic attacks deal 6% of the target's current health (min 10) in bonus on-hit physical damage (max 60 vs. minions and monsters).

Active: Deals 10% of target champion's maximum Health (min 100) as physical damage, heals for the same amount, and steals 25% of the target's Movement Speed for 3 seconds. (550 range and 90 second cooldown)

Rageblade Stats Price: 2800 +30 attack damage +40 ability power

Unique: Basic attacks (on-attack) grant 2 stacks. At 8 stacks, gain Guinsoo's Rage. A stack grants +8% attack speed, +3 attack damage and +4 ability power for 5 seconds, stacking up to 8 times, granting a total of +64% attack speed, +24 attack damage and +32 ability power.

Unique – Guinsoo's Rage: Deal 20 (+ 15% bonus AD) (+ 7.5% AP) on-hit magic damage to the target and nearby units in a 350 units radius area of effect.

---

I'm not a Trundle main at all, but honestly? It seems like Rageblade is the better choice. As it gives more damage to your ultimate for the tanks that you're eventually going to be fighting and it gives you the combat-ability and damage.

While BOTRK's damage is more instant, with Rageblade both being cheaper and giving more inital attack damage, it just seems to be the better item for Trundle than BORTK is. But, I'm not a Trundle main.

Can someone point out which would actually end up being the better item for the trollking? (As a top laner preferably)