Ok so, I went through this exact same thing last year. I've been shooting with the 5D IV for ages, but I'm lowkey new to the wedding flash world. Honestly, I started with the Canon Speedlite 600EX II-RT because I was terrified of third-party gear failing, but that price tag is actually wild. Basically, I eventually tried the Godox V1-C Flash for Canon and the technical difference in recycle speed is literally night and day because of that lithium battery. No more fumbling with AAs!! One thing I noticed technically is that the AF assist beam on my Godox V860III-C for Canon doesnt always line up perfectly with the 5D IV's focus points in pitch black. It's a bit less precise than the native Canon grid, which was a learning curve for me. Anyway, the Godox system has been surprisingly reliable for my gigs so far... gl with ur choice!

Respectfully, I'd consider another option. I know everyone is obsessed with the V1 lately, but honestly, you don't really need the round head for wedding work starting out. If you're trying to be smart with your money, I'd suggest the Godox V860III-C Li-ion Flash for Canon instead. - It's basically the same internals as the V1 but with a standard head, making it way more budget-friendly.
- The Godox VB26A Rechargeable Lithium-Ion Battery is the real MVP—recycles are sooo much faster than those old AAs, which is huge for receptions.
- E-TTL on the 5D IV is super reliable now, so consistency isn't really an issue anymore, iirc. Seriously, you're gonna save like $100. Use that to grab a Godox XProII-C TTL Wireless Flash Trigger for Canon so you can get that flash off-camera for portraits later on. It's such a better value play for a working pro, right? gl!

Adding my two cents here, but i honestly think sticking with native gear is the smarter move for professional work. I've been doing this a long time and i've seen way too many third-party units glitch out at the worst possible moment during a reception.

• The communication between the body and flash is just flawless when you stay on-brand.
• Native AF assist beams are much more reliable when the 5D IV is hunting in dark corners.
• I've found that the color consistency is just better across a whole day of shooting. Basically, just go with any professional-tier flash from Canon. You really cant go wrong staying within their ecosystem if reliability is your top priority.

Basically, if youre doing weddings on a 5D IV, you really cant afford a gear failure during the ceremony or the first dance. I'm pretty cautious when it comes to certain third-party brands because I've had units overheat or just straight up stop talking to the camera body in the middle of a set. Honestly, go with Profoto, you can't go wrong if you want that rock-solid reliability. * The thermal management is way more advanced, so it wont lock up on you during heavy bursts.
* The AF assist is usually much more dependable than the budget alternatives.
* The consistency in exposure and color is just way better for high-volume work. Its a bit more of an investment upfront, but not having to worry about your equipment failing during a once-in-a-lifetime moment is worth it tbh. I've been using their stuff for a while and it's never let me down lol.

Yep been there done that. Can confirm everything said above is spot on.