It is very usefull for alakazam and machamp solo raids! And of course also good against psycho cut/fb or hb mewtwo :) i am very satisfied with mine (82% lvl 39 14att legacy shadowclaw/sb)! I also managed to catch a 100% gengar (hex/sb) thanks to a gengar solo raid but don't plan to max him out because of hex. If you're short on stardust leave it be because nevertheless gengar is not a must have even with legacy sc.
GamePress
Gengar question
I have a powered up Gengar (lvl 31,5, 80% IV) with Hex/SB and I really never use it. Now I have another legacy Gengar lvl 20, 89% IV, 15 Attack with SC/SW (both legacy).
Now the first question is what you use your Gengar for? Is he really a good choice against Mewto when dying after 4 or 5 Confusions? Would you then CTM away Sludge Wave for SB or would you keep the legacy move? I have other good counters so there is no pressing need but I would consider pushing it to lvl 31,5 too if you're telling me he's still awesome and worth it to get some extra balls even though he dies quickly. Or is there an important brrakpoint which I must reach to make him worth? Is he a must habe for a good trainer? Thanks.