There are humdreds of posts out there on putting your Bug-Out-Bag together. What to include in it, what not to include in it, essentials, just-in-case, and so on. I've even done a few posts like that including - The most important Thing You Should Consider When Creating a Bug-Out-Bag. What few do talk about is how to choose the right Bug-Out-Bag for you.
First, should come fit and with fit comfort. You don't want to lug around a bag weighing 50, 70, 80 or even 100 pounds of weight without it being comfortable. Also, you want it to fit right. The most practical choice for many is the backpack and you want to be certain you can wear it and be able to move freely with it on.
Second, You want to be able to access at least some items rapidly and easily. Certain bags lend themselves to this category easily, others do not. Also, depending on your size and body type it may be easier for you to use one type of bag but the same bag for someone else they may have difficulty reaching an item.
With both of these thing in mind, going out and trying different types of bags on for size may be best. This is especially true if you have never tried one before. If you are unsure, go to a camping goods or outdoor store and ask for help. Many of the stores have people trained to help you find the right fit. A good idea is if you find one that you would be comfortable hiking or camping with, it will likely make a good Bug-Out-Bag. The only exception here is that I would not choose a brightly colored bag.
The next thing to consider is what you need to place into the bag, and how much the maximum weight you want the bag to be at. Then find ways to reduce the pack load any way you can.
Finally, make sure that you are able to carry everything you need inside that Bug-Out-Bag that you would need to reach your destination. Another good idea is to have places with items cached along the route you will be traveling.
Below are some of the types of bags I use. Yes, I have different ones, but I also use them to show other people. The most important thing about choosing the right Bug-Out-Bag is picking the right one for you.