Overview
UMP40 is a non-stop comedy of failed gimmicks. Her base stats are the best quality about her, being in the middle of the other two UMP dolls, who both have fairly good base stats as well. Her skill either makes her take a ridiculously long time to reach an evasion buff that is not worth the 10 seconds you spent waiting on it, or a damage buff that takes a similarly long time to reach its peak. While the damage buff is powerful on paper, it comes with the downside of completely crippling her for the rest of the fight. Her tiles are unique, but being unique definitely does not guarantee usefulness, as her tile buffs are near useless for SMGs, with the added downside of not being able to buff your ARs (or, in other terms, your actual DPS for an ARSMG team).
Pros
Decent Base Stats
UMP40 has fairly decent all-around base stats for an SMG with nothing that stands out as being particularly bad.
Cons
Useless Tile Buff
UMP40 is unique in that she is one of only two SMGs that can buff other SMGs. This is not nearly as useful as it seems.
Incredibly Long Startup Time
Both UMP40’s passive and active take a great deal of time to hit their maximum potential, to the point where almost every fight would have ended or been almost over by the time she hits her stride.
Crippling Self-Debuff from Active
While UMP40’s Active skill gives her a huge self buff to her Damage at maximum stacks, it also makes her Evasion drop massively, and there is no way to switch modes once her Active has been triggered.
Full analysis
As mentioned in her Overview, UMP40’s base stats are decent. Being in the middle between UMP9 and UMP45, UMP40’s stats fill in a sort of middle ground of SMGs with decent stats, with no stats that are especially noteworthy in terms of highs or lows. It’s all downhill from here.
UMP40’s skill, Etching Overload, has a cool name, but completely awful in-battle performance. Due to the Skill’s CD of OVER 11 MINUTES, UMP40 is effectively locked into one of two modes for the duration of any fight. Using her Passive, UMP40 slowly builds stacks of Evasion at the expense of some Damage over the course of 10 seconds, capping out at an Evasion self buff of 61% for the rest of the fight, which is probably already over by that point. By comparison, C-MS has a 65% Evasion self buff at 1 SECOND into any fight in her Evasion mode, with equivalent base Evasion to UMP40. The other half of UMP40’s skill gives her a stacking damage buff, which takes a minimum of 11 seconds to reach its peak, assuming you activate it as soon as possible. The self Damage buff is huge, maxing out at 271%, however, it comes with an also-massive Evasion debuff, which utterly cripples UMP40’s survivability and makes it near-impossible for her to tank. Also by comparison, SR-3MP has a 260% self Damage buff with an ICD of 4 seconds, and doesn’t reduce her evasion to almost nothing.
UMP40’s tile buff looks really strong at first glance, being a 500% buff to her fellow SMGs’ Crit Rate. However, it is far less impressive than it seems. With SMGs having a base Crit Rate of 5%, this tile buff will only result in a +25% Crit Rate boost, unless they equip a Suppressor or Crit Scope. Trying to equip a Crit Scope on any SMG is a bad idea unless the SMG is a DPS Off-Tank fighting 0 Evasion enemies, and the SMGs who would get the most out of a Suppressor wouldn’t get anything out of UMP40’s tile buffs. Also, her tiles have a glaring flaw in being entirely unable to buff your ARs, which should be your main damage dealers (and the focus of your buffs) in any ARSMG team.
Overall, UMP40 is a sad sack of failed experimentation. Decent base stats mean nothing if her skill and tiles can’t effectively contribute to any team or fight.