I currently run a wp/woocommerce site that's been optimized as far as I can take it for an Apache server:
MySQL memory optimized WP Rocket MaxCDN
VPS: 2 cores 2 gigs of ram SSL
The site offers about 50 different services while it updates & cycles through orders every hour. It's a WP/WC site so it has a small blog and account area for customers. There will also have some free web based tools available soon.
My biggest bottleneck is probably PHP and around 70 requests to the server on page load.
From what I've been reading Litespeed is still faster, but I'm not sure if I'll see much of an improvement if my apache server is already optimized, especially if I change to fastcgi. Also, it's not very clear to me what some of the limitations may be. The last thing I want is to change web servers to find parts of my site stopped functioning.
Do I need to worry about my PHP scripts not working with LiteSpeed, or can Litespeed handle everything you could throw at an apache server?