I remember doing a high-stakes shoot in a damp forest once and my knock-off grip just stopped communicating with the camera halfway through. I spent half the time fiddling with the dial instead of actually shooting... total disaster. If youre stuck between that $300 price tag and the cheap plastic feel of the really low-end stuff, Ive had decent luck with the Meike MK-5D4 Pro Battery Grip for Canon 5D Mark IV. It is usually under $100 and honestly feels more substantial than the Neewer ones. It has some basic weather sealing gaskets which is a huge deal if you are worried about that Seattle mist. Since your wedding is this weekend tho, have you considered just renting? For like 30 bucks you can get the real Canon BG-E20 Battery Grip for EOS 5D Mark IV from a local shop. It buys you peace of mind because you know the magnesium alloy build will actually hold up under pressure. If you are dead set on buying right now, the Meike is a decent option. The buttons have a more tactile click than the Vello, though its still not a tank like the official one. Just make sure to wipe the gold contacts with some isopropyl alcohol before you mount it. Sometimes those factory residues are what cause the connection drops people complain about. Its not a permanent fix for a pro career but it works for a tight spot.

TL;DR: Buy used OEM or the Pixel clone. Most cheap options skip the weather sealing, which is a total nightmare for Seattle weather. I've had issues with the dials skipping on those generic ones before. If $300 is too much, find a used Canon BG-E20 Battery Grip for 5D Mark IV. The only decent alternative is the Pixel Vertax III D18 Battery Grip for 5D Mark IV because it actually fits tight and doesnt rattle.

It is honestly such a letdown when your gear starts acting up right before a major wedding. I have had issues with various third-party options over the years and unfortunately, most of them are just not as good as expected when you are shooting in a fast-paced environment. The connection dropping mid-burst is the absolute worst.

• Go with Phottix as they are generally more reliable
• Avoid the super cheap brands found on generic marketplaces
• Look for something with reinforced contact points If you really cannot swing the official version, just get any grip from Phottix. You basically cannot go wrong with their stuff compared to the really flimsy alternatives. It still wont feel exactly like the native one, but it should get you through the weekend without those annoying glitches.