Blissey with P/DG. Is it good enough?

P/DG is very good and ZH/HB is too easy to dodge, but the problem isn't the moveset it's probably the location you placed the Blissey in. If a Blissey is going down it's going down regardless of the moveset. I like P/DG alot it's prob the most versatile moveset for her.

Here, in my local biome, Blissey is a considered a magnet. Yes, it is an awesome defender... Arguably the best due to toughness and timeout probability but people tend to test that fact. Plus, it's the best Pokémon to practice your strongest mons. Seeing your pride and joy Dragonite destroy the so-called best defender in the gane is just satisfying. Anyway... To answer your question, I believe that Blissey's greatest threat is her bulk. Causing players to timeout. While ZH/DG is arguably its best defensive moveset, Any powered up Blissey is a pain to tackle. If I were you, I'd be happy I have one. Just don't rush. You'll get her eventually. Up to you if you want to max your current one. If you're lacking defenders, you can probably do so.

It will do very well on attack and defence.

For me P/DG is the more versatile and the best Blissey moveset at this point, the only benefit of ZH is that is SE against fighting mon that will probably attack Blissey, but anyway P will fire more often and does benefit from STAB.

I would power up P/DG to the max, I have done it and now it is a beast with 3033CP, no regrets at all. As long as you don't get Psychic for me any Blissey is a must power up. And if you get DG any quick move is more than perfect.

Bring that Blissey (regardless of moveset) above 3k if you can.

Of course some of Blissey's movesets are better than others but a high CP Blissey is a pain to deal with, first and foremost. Secondly if it comes to defensive moves then I would rate P/DG as 2nd best being SE against Dragonite and Tyranitar and Machamp, its 3 most common and arguably most effective attackers.

IVs are just as important as moveset for answering this question. What are each IV and current level or CP?

Something like 15a/15d/0s could be worth powering up. 0a/15d/15s, not so much.

Moveset isn't that important that it get kicks out immediately or not. Someone decides to take a gym down, whether it has P/DG, ZH/DG or P/P.
Trained a gym and put my blissey ZH/DG in it, was level 8 with 4 blisseys, gone in a day.
But to answer your question, P/DG is good. only ZH/DG is better. Also i have the feeling that Blissey attracks attackers to try it out.

I have three 2900+ Blisseys
P/DG
P/HB
P/P
All three are in my team gym territory, and all three tend to sit, gather coins, and look nasty. So in summary it's the CP that matters.