I have custom plugs and custom IEM's. The custom plugs were AMAZING. Yes, you need to go get your ears fitted and they cost a bit more, but you can get filters with different db killers. I opted for the most isolating ones as my band is very loud. The best part of this is that they bring the sound down evenly. using regular construction plugs, or the cans over your ears cut out a ton of highs and alter the sound. With the customs the sound is exactly the same, just quieter. Plus they can stay in for hours. I can only wear the cans or non custom plugs for so long before it's uncomfortable.
The custom IEM's double up as really good isolation too. I just put my UE5's in and leave em unplugged. I can wear them for hours as well. The only difference is that they don't have the filters.
Custom fitted is where it's at, if you can afford them. Just decide if you want hearing protection or IEMS. the nice thing about the custom IEM's is that you can mic up your kit, turn the volume to a very low level and still hear everything perfectly.