400 crit damage is the only thing going for it and it loses that advantage in favor of the pve legendary's flat percent crit chance and damage as stats have diminishing returns. I really don't think it's worth it as a pve weapon. I don't know if there's an internal cooldown or what the proc chance is. You deal 3,000 extra damage and recover 3,000 hp. Seems like it should work just like life drain gems except randomly instead of on crit. I don't have any way to test the weapon so I'm guessing here about 3,000 life drain. Unrefined to stage 1 gives nothing, stage 2 gives the galaxy buff and stage 3 400 crit damage. Note that galaxy gets its worth at stage 3. I'm basing stats of galaxy, emperor, and chokma off of kr version. Not that you couldn't use an emperor weapon in pve, but it wouldn't be nearly as good as chokma. For now, galaxy is basically equal or slightly worse than baleful depending on the situation but baleful and its upgrades will specialize better in pve stats and effects and class skill bonuses so the pve gap widens. If you want your weapon to be competitive in pve in the future, then no, stay with baleful/seraph. If you have any further questions, fire away. I've been caught in floor 50+ ToI DES Fury combo at half health with no escapes, and walked away alive. You're basically invincible for its duration while also gaining major offensive buffs. 50 Attack Power -10k HP -10k Defense -500 Crit & Piercing -2,500 Combat Health Regen -500 additional damage -Resets skill cooldowns after it expires. On 10th stack it unleashes and gives you the following buffs for 30 seconds: You gain 5 ATTACK POWER for every stack of the buff, and a 2000 heal when hit. Unlike Baleful's proc which is trash, Galaxy is incredible.

One thing that definitely makes Galaxy weapon a great one.

However, there's one thing people have failed to mention so far. Stage 3's additional crit damage is always welcome too. I haven't paid a close attention to its proc rate, but it seems frequent enough. The 3000 HP leech is indeed vampiric and does deal 3000 damage. You can even farm 99% of the mats on your main. I can see Galaxy being a great cheaper alternative for maybe some forgotten lvl 45 era alts you'd like to revive. Baleful and Seraph are still better long term investments. It's good even for PvE if Baleful/Seraph class specific effect isn't crucial one. Cost should be comparable to true scorp if starting from 'scratch' but with much, much less farming. Galaxy weapon is very solid for how cheap and easy it is to obtain. (It cost me 1600g ish for stage 3) Right away I'm going to say that I do not have any minmaxed calculations to give you, I'm simply providing my opinion on the weapon.

Blade and soul galaxy weapon