I know, I know, the lingo is intense. It's hard to choose a service when you're unfamiliar with these terms. I'll explain what each of them means and their benefits to give you a better understanding of what you're getting yourself into.
Classic Eyelash Extensions-
These are the original technique of extensions. One, eyelash extension is applied to one, isolated, natural lash. You can get as full as you have natural lashes, so if you want a very full look and you have sparse lashes, this isn't going to be your best option. Now, years have obviously passed since this began, so materials and styles have given more variety and potential to this type of set. There are different diameters, curls, lengths and colors to really customize the look. This is best for lash newbies or those who want a natural look or who have a full lash line. Not to say anyone outside of those parameters shouldn't get it done, but since you can only get as full as you have of natural lashes, you're limited.
Hybrid Eyelash Extensions-
This service combines both techniques of classic and volume to create the best of both worlds. With both techniques, this is a great introduction to volume and seeing the potential it can give. It also is great for those who need just a bit more volume or sparse areas.
Volume Eyelash Extensions-
When you want VOLUME, you get these. During the service, we are hand-making volume fans to apply to one, isolated, natural lash. This creates a fluffy, full set of lashes. Each volume fan has anywhere from 2-6 lashes on it, creating fullness that you may not have naturally. This is why it's amazing for those who have a sparse lash line, fine lashes or those who want really full lashes.
Mega Volume Eyelash Extensions- Now, this is a new one, but there are multiple ways to do this type of set and they have different
looks. I personally trained with a technique that focuses on density by using shorter lengths and focusing on perfect fans. There are other techniques which use longer lengths and create what's called a bouquet fan. Many times, these are really full but really long. It's not necessarily my style, which is why I haven't trained in it yet. The technique I use also focuses on layers and creating a clean line. I'm still messing with this technique and figuring out how I like styling the best, but this is best if you have a special occasion coming up or you want your lashes to be very dense and full.
Hope that gives you a better idea :)