Was coming here to post this.
What's important is that people don't get too hyped about this being a "game changer", because it's not. Certainly, having another medium / long range, precision weapon in their arsenal will increase Ukraine's war capability. Furthermore, its relatively low cost of GLSDB makes it an attractive alternative to expensive cruise missiles that are in low supply, as well as GMLRS when the latter is out of range. Ultimately, Russia will be forced to keep more key assets further from the front, which makes their logistics chains longer and less efficient. GLSDB's 150km range is certainly going to be a welcomed addition to Ukraine's war arsenal.
Context is important, however. While eventually a significant supply of GLSDB with likely be available, Boeing only expects to manufacturer between 750-1000 units this year, with some of those going to the U.S. Army. Production will expand further in 2025 depending on orders. That means in 2024 it's reasonable to think Ukraine will get about half of the GLSDB produced, which means they'll receive roughly 375-500 units. That's not an insignificant quantity, but it's not a game changing quantity either. It's not as if they'll be plentiful in quanties numbering in the thousands like GMLRS is (and has been).
The way we should think of GLSDB is simply another option, that fills a range gap in the world of precision strike capability. Ukraine now has JDAM and AASM bomb kits (and soon the F-16s to use them property), APKWS rockets, GPS guided 155mm artillery shells and various forms of kamikaze drones, to perform short / intermediate range strikes. GMLRS and GLSDB will handle longer range strikes, while Storm Shadow / SCALP-EG and ATACMS (if they receive more) will handle the extremely long strikes. Ultimately, GLSDB allows you to save a cruise missile or an ATACM missile that would have otherwise been used to strike a Russian asset in the 100-150km range.
What I'll be most interested in seeing is what the Russian intercept rate of GLSDB is like. Russian air defense assets have routinely been challenged when it comes to intercepting GMLRS and cruise missiles (especially when combined with MALD decoys). A lot of Russia's BUK, OSA, Pantsir and Strela air defense systems might be forced back onto the Russian side of the border if they prove incapable of saving themselves from GLSDB strikes. That would present a significant challenge to the Russians as it would allow Ukrainian CAS greater ability to operate near the front, under the radar coverage of Russia's S-300 / S-400 systems.
