[outdated] Caustic Arrow Solo Map MFer (20/300+)

Passive Tree
Unless you are running one of the CI CA builds the trees are very similar. There are only a few nodes that can scale the cloud damage, and only so many places to get life and defenses from the tree. As such the difference between the two trees are very minor. Both trees are also posted at about level 90 having run all four of the Lord's Labyrinth.

This build's tree takes the life node under Golmn's Blood, the life node leading to Master of the Arena, Master of the Arena, Piercing Shots, another life node in the Scion 'wheel', and two more frenzy charges. The High Speed build uses those 9 passive points to fill out Phase Acrobatics, and allocate all of the Shadow's starting Chaos/Phys nodes. Also this build takes Soul Siphon, and the other takes Primal Spirit.

It comes down to personal preference of play style and understanding of mechanics as to which tree you favor. You can make the decision about number of frenzy charges, using Bloodrage, completing Acrobatics and Phase Acrobatics, and total life pool.

Gearing
Primary differences this build suggests Carcass Jack/rare chest, a rare belt, Goldwyrm boots, and Andvarius gold rings. While the other build requires Queen of the Forest, and suggests Perandus Blazon cloth belt, rare boots, and Ventor's Gamble gold rings.

Carcass Jack is the only chest to provide a damage boost to the main skill, and a rare chest will help make up the resistances and additional life. A rare belt is a great way to get a lot of life, resistances, and if going for min/max potential, movement speed. Goldwyrm boots are a little slow with only 10MS on them, but they provide all your quantity in one item and a lot of fire resistance. Serleth has gone in depth about the difference between the unique gold rings. You can find a link to the math and discussion in the FAQ post.

On the other side you have Queen of the Forest, which has a decent life roll, some resistances, and can really up your movement speed. Perandus Blazon provides a lot of all stats, some quantity, and a little fire resistance. A rare pair of boots can have up to 30MS, resistance, life and evasion to scale QotF.

When trying to get the best out of the 'C' value for magic find, I think this build has the better ratio. Having fast movement speed is really nice. You could even try out the gear as it is in this guide and swap the chest for QotF and see how you like the slight boost to MS, assuming you are resistance capped. Also what you can find and afford plays into the decisions too. Movement wise you are looking at a difference between ~20MS vs ~50MS.

Gems & Links
Pretty basic and mostly the same between the two builds. The big difference is this guide notes the max Intelligence needed for a 21 Concentrated Effect, and it an reach that goal via the passive tree. So no other int is needed on gear. The High Speed guide has many of the gems leveled all the way to 20, and more int is needed on gear. This is likely one of the additional reasons for running Blazon.

The gem level suggestions in this build are more to the mindset of min/max. There is no added benefit from having more levels in Faster Casting, Wither, Vuln, or Curse on Hit. Not needing any extra int on gear frees up suffix spots for more resistances, rarity, or the new essence chaos damage.

I think those are the major differences between the builds, and even then they are not that major. I'll also note the reason I got involved in this thread is the sense of community around the build. Serleth and the regular posters answer all manner of questions, go in depth where able, post with some sense of humor, and are generally supportive.