Their stuff is pretty good, but expensive. They have BUNDLES now (sort of miffed on that one, as I spent a ton of money to buy stuff individually right before the bundles came out.)
I guess it depends on what you are trying to write? I’d recommend the BML stuff over the Sable stuff for orchestral work, but damn, the Sable stuff sounds good. Albion is still a pretty good value for coloring things.
If your serious about using the spitfire libraries, just make sure you have a fast enough computer with enough memory. I’ve got 32 gigs of RAM and a SSD and it is just barely covering it. For me, it’s worth it to not have to not EQ and mix a bunch of instruments and have things sound good (more-or-less) out of the box. It’s also worth it to me to pay the bit extra to not have to deal with ILOK DRM bullcrap (ala East West.)
Buying stuff from Spitfire isn’t the greatest. Not only do they not accept Paypal anymore but they take a day or two to process your credit card payment before they send you download links - at least they did for me.
Finally, a lot of the libraries don’t work like they do in their videos. All the BML Mural String libraries no longer have master patches with all the articulations and keyswitches, so if your used to keyswitching, fugitaboutit. Some of the BML libraries are lacking, in terms of things like you need to buy BML Mural vol 2 to get tremolo patches for all the strings (what?) the Trombone library doesn’t have a solo patch, just a2 (What?) the horn library doesn’t have an a4 patch just a2 (what?) ect…hopefully they release other volumes in the future for these kind of things.