Saw this today and had to jump in cuz I went through the exact same struggle when I started shooting weddings! I tried the official Canon BG-E20 Battery Grip for EOS 5D Mark IV and while it is built like a tank with amazing weather sealing, the price is wild. I tested others for my second shooter and here is the technical breakdown.

• Vello BG-C14 Battery Grip for Canon 5D Mark IV is legit the best bang for your buck. The button tactile feedback is nearly identical to the camera itself which is huge for fast shooting!
• Neewer Vertical Battery Grip for Canon EOS 5D Mark IV is a budget king, but the dials feel a bit clicky and thin imo. I once had a super cheap grip lose contact mid-ceremony... literal heart attack! If you want reliability without the Canon tax, go Vello. The electronics are way more stable for long days.

Stumbled on this today and had to chime in! @Reply #2 - good point! If you want solid performance without the Canon price tag, check these:

• Vello BG-C14 Battery Grip for Canon 5D Mark IV: This is amazing! It feels high-end and fits perfectly.
• Meike MK-5DR Vertical Battery Grip: Fantastic value! It even includes a wireless remote. I dont think youll regret either for the wedding shoot!

Ngl, the official Canon gear is ridiculously overpriced sometimes. I totally get the hesitation with the budget. I actually used a third-party one on my old 5D for years without it exploding or anything, but you really gotta be careful with the build quality. Some of those cheap knockoffs feel like they are gonna snap if you tighten the screw too much, which is the last thing you want when you are working a high-stakes wedding. Honestly, are you more worried about the grip failing mechanically, or is it more about the weather sealing? Seattle is famous for being damp as heck in the fall, so if you are shooting outdoors, that cheap plastic might not hold up as well as you would like. Also, how much are you actually looking to spend? There are some mid-range brands that bridge the gap between the thirty dollar junk and the official three hundred dollar one, but it helps to know what too expensive means for you right now.