I've run both SPC and trans at the same time testing it out and that combo was just too squishy imo. I now run an Argonian Warden with a full set of Legendary Heavy Seducers with everything Impentrable. I also run purple Transmutation on backbar with legendary shield and a dagger, followed up with the jewelry; I'm waiting for murkmire staff for front bar.
With my playstyle and the healing output I already give the team in BGs, I felt Transmutation might be less impactful over something that may help them further captilize on kills, like SPC. If I run SPC, I could easily slot in Pierce Armor into my rotation and make it work with my playstyle.
As a Warden, I use Nature's Grasp as my gap closer which lets me hookshot to a DPS. When I play with my team, I usually have an initiator who dives into a team. I follow up with Nature's Grasp and then Sleet Storm + Time Freeze on top of them. I am then right by the enemy and, since my entire team is getting healed from like 6 HoT's and Sleet Storm's "Major Protection", I am able to debuff with Pierce Armor to help them get the picks they need.
I also far prefer Bogdan's over Earthgore, it's just better if you look at the stats imo.
Earthgore for me is healing for 39,132 health over 6 seconds, that's roughly 6,522 health every second, and in PvP which halves it, it's only 3,261.
Bogdan's on the other hand is 4543 health every second for 6 seconds; that's 2,271 in PvP every second. Earthgore, which is a much bigger area of effect, has that 35 second cooldown while Bogdan's is always up for me because I run like 6 regens or so. It is consistently healing and procing at the right times. Earthgore is only a little stronger, roughly 989 healing more than Bogdans, which doesn't make me want to run it. Earthgore does have it's place although, like in Cyrodil in big groups; however, in smaller scale PvP like this scenario talking about SPC and Pierce Armor, I think Bogdan's is better by far.
People will tell you Bogdan is trash.
I’ve been using it for over a year at least. I love it on multiple classes. Especially Werewolf.
For those that were confused, like me, Bogdan is called The Nightflame Set.