You’ll get a ton of stuff for $150, it’s a pretty insane deal for what you get vs what you pay. You might not get all of the most recently released stuff, and it’s not always easy to see exactly what is included vs what isn’t. If there is anything you particularly want, double check if it’s in there.
If you own none of it already, then it’s a great deal. If you own 99% of it already then you usually end up paying the same price for the last remaining bits as a new customer would for everything. Lots of companies operate like this. Just be warned if something comes out that you want that your options will not represent the same value as offers like this.
I actually think the quality of many IK plugins is better than they get credit for, but they have some long standing bugs that don’t seem like they’ll ever get fixed. Their customer service and support is generally pretty poor - you can file bug reports, logs, video demonstrations and steps to recreate the bugs and they’ll gaslight you or ask for more proof of it, or try to send you in a loop as opposed to fixing it. They’re generally quite stable but you just have to keep an eye out for goofiness, especially when using different sample rates or if you need latency compensation to line up correctly (like when something is bypassed).
IMO the products are largely better than the service/overall experience, so while you get good value with the products it’s the other areas that suffer. Another thing to consider is so much of IK’s product line is them copying products from other companies. Say you want a Manley Vari Mu, or 1073, or 1176 or LA2A, you can get officially licenced versions from UAD.