Summon Gargoyle is a 21 point deep Unholy talent. Maximum duration 1 minute. The Gargoyle requires 50 Runic Power to be summoned and then 8 Runic Power for every second past that. So for it to last the whole full minute, you will need to generate around450 Runic Power over the duration of a minute. As Unholy, the optimal RP generation is 8 RP/s which will grant you 480 RP/minute. If you summon the Gargoyle at 100 RP, you will need to generate 250 RP over the next minute.

What this means is that it's rather tight to generate enough Runic Power to keep the Gargoyle up a whole minute and get a DC or two off, but it is very possible. As Blood, it's recommended to only use Sudden Doom proc Death Coils though.

The best time to summon a Gargoyle is when you have as many attack power multipliers up as possible, as the Gargoyle will only check your AP when you summon it. So if you summon it with f.ex Rune of the Fallen Crusader proc, DMF trinket proc, Mirror of Truth proc and Call of the Wild (Hunter pet buff) your Gargoyle will do increased damage for the entire duration.

The biggest issue with the Gargoyle is how squishy it is (and as of now gets summoned with half HP, which doesn't help). We are not sure if Night of the Dead will affect Gargoyle, but let us hope.

DRW is the 51 point talent in Blood. It spawns a copy of your weapon, which copies your attacks. The maximum duration is 22 seconds. Dancing Rune Weapon should ONLY be used when you have 100 Runic Power. Any number below that will make it a waste, significantly reducing its uptime.

It's major downside is that you will need to be hitting the boss for the duration of it's uptime and the fact it does not inherit your hit and expertise stats significantly increasing it's misstate. It's unsure if this is a bug or not. The major upside of DRW is that it can't die.

A neat thing about DRW is that you can make it copies exactly everything you do. This includes summoning a Ghoul or even Army of the Dead! It also puts Hysteria on itself, but it's not clear if that actually increases its damage. Sometimes it'll put the Hysteria on you but a first test showed it would not increase your physical damage. It's very hard to replicate though, so very hard to test.

Summon Gargoyle vs Dancing Rune Weapon: this comparison is for the 50/00/21 spec obviously. Summon Gargoyle has the advantage that it scales way better with starting gear, while DRW gets SIGNIFICANTLY better with every weapon upgrade.

For Dancing Rune Weapon to become better than Summon Gargoyle, it will need to do more DPS in 22 seconds (in combination with your Death Coils) than Summon Gargoyle will do in a whole minute. Whether that's the case for every gearprogression, is hard to say right now.

Dancing Rune Weapon has the additional benefit that it's a fire and forget button. Summon Gargoyle will require some effort to keep up, which won't always be possible. They both have their ups and downs and it's just too early to say which one is the better one until we've seen some more in game numbers. Again, the biggest problem is that Gargoyle dies too quick. It does significantly more DPS than DRW at the moment though, so on fights where it won't die and you can keep it up the entire duration, it's the better choice than DRW.