Here’s my thoughts on general recommendations to anyone thinking of buying one. First of all, do it! You’ll never want to shoot loud again. As for what order to buy:
1 - Something practical. These things are expensive and for a first choice getting a broadly useful can makes a lot of sense. For a semi-auto rifle, get a general purpose .30 cal to cover 5.56 to 300 BLK to .308. For a PCC, whatever caliber you have. 9mm, 45, etc. If it’s for a bolt action , a direct thread lightweight can will be a huge improvement in quality of life for hunting where ear protection isn’t as widely used.
2 - 22LR. This is the way to Hollywood Quiet and by far the most fun.
3a - If you hunt, a lightweight direct thread for hunting, assuming you didn’t buy this one first.
3b - If you don’t hunt, get a handgun caliber with the booster, if necessary.
Everything after this is likely going to more niche or caliber or gun specific. By this point you’ll have made plenty of your own opinions and preferences.