Just sharing my experiences and 2 cents on the topic. YMMV. just a fyi, im a 100% stock guy but my bro uses 100% chassis. Ill try to list some "topics" below with discussion.
1. Cost savings (chassis > stock)
-prob the most impt factor for people. I would say a cheap chassis will pretty much always give you more bang for your buck when it comes to budget options. By bang for your buck im talking adjustable LOP / cheek, arca rail or picatinny attachment, etc. Greatest example i can think of is the KRG bravo. Prob my #1 recommendation for any new shooter or person who wants to dip their toes into the aftermarket realm and itll only set them back around 350$. There is a hidden cost behind stocks that most dont realize. Yes you can buy a mini chassis from manners and itll fit pretty much all rem 700 models, but if you go with a custom action you might have issues with bolt hand clearance, side bolt release, or action eject port alignment. These things r non existent issues on a chassis. ANother thing is you might need to end up bedding a stock to get a better fit. So yes you could buy a mcmillan a5 for maybe 500 bucks, but then you need to add a m5 DBM (200ish), then possibly bed (up to 400$) and now your mcmillan is a 1100 dolllar investment that really is married up to one receiver. Oh and if you want more modularity such as a arca rail, then you can either drill and bed T nuts yourself and possibly ruin it aesthetically, or send it off to a gunsmith for an extra added fee. I would say the cheapest stock i would buy would be a grayboe (same company as mcmillan pretty much) which costs around 500ish for non adjustable a5 with DBM included.
2. Features (chassis > stock)
-As a stock guy, adjustability and modularity is something that will always be lagging behind the chassis community. There are stocks that are finally getting the message and we are seeing things such as the Manners PRS-TCS. The issue with most stocks is that you are "fixed" when it comes to features such as palm swell to trigger distance, pistol grip thickness / shape, weight, and action compatibility. Its hard to explain, but if you ever get behind a manners, mcmillan, and foundation stock. Each has unique palm swells and hand feel. Theres really no way to adjust that unless you purchase a different variation amongst them (such as foundations exodus, genesis, and centurion). And its not very realistic to go out and feel each one since our prs community here is nill and ive probably seen only a handful of higher end stuff at the range (definately see way more chassis than stocks)j.
3. Feel (subjective, but i say stock > chassis by a landslide)
IMO what makes the feel of a stock great is the material that is used. There is something about the warmth and density of a fiberglass molded stock or micarta (foundation) or wood that cannot be replicated by a chassis. That interferance between the shooters hand and stock to me is what gets me and makes me willing to put up with every other irritating / costly factor. I would definitely recomend anyone get behind a mcmillan A5 or manners or foundation stock and just popoff a couple rounds, its def eye opening and makes u feel "justified" spending the money. But like i said above, stocks are SOOO varied with grips and hand placement that its hard to figure out which one youd like. I usually take my foundation (vuddo 22) and mcmillan a5 to the range and have let multiple people shoot each one just so they can test it out. Also when you shoot a top quality stock, the gun has a sort of dead feeling when it goes off. Most chassis, regardless of price, will have a sort of twang or ring to it when shooting due to metal vibration. Chassis do however allow you to adjust almost all grip positions (MPA, etc) and customize your hand placement. The downside is the "feel" of the grip. Chassis always inherently use a plasticy or metal feel to their grips which IMO just dont feel as great. But like i said, you just need to feel it to figure out which one you like best. The ARC xylo does try to blend this by using wooden a5 style grip onto a metal chassis giving you the best of both worlds.
4. Availability (Tie ish)
The only real issue with stocks is if you want a truly custom order. If you can settle for a color you may not like or missing on minor features, the mcmillan site or manners site or ALTUS always have a wide variety in stock. I usually just buy the model i want and maybe send off for cerakote or other smithing work in the feature.
5. Application / weight (tie)
I was gonna say stocks easily have the advantage for weight and hunting. But there are some solid options for chassis now that make it practical. for example my hunting build on a gunwerks magnus carbon stock with carbon barrel is similar in weight to my brothers MPA ultralight chassis with carbon barrel. His build could be lighter if he went to another chassis such as the new ish XLR magnessium chassis.
6. Options (tie)
Both stock and chassis brands and models have exploded over the last 5 ish years. So there is a huge plethora of options for one to chose from, both in the budget and higher end stuff.
For me personally my favorites are going to be
1. Mcmillan A5 (best feel of any stock ive laid behind)
2. Paradigm carbon a5
3. Foundation genesis (its reach is slightly farther from trigger than the mcmillan so thats why its lower rated). It does feel nice tho with the micarta material.
4. Magnus from gunwerks (grip is a touch too slim but it works well for hunting)
5. Manners T6A (idk why but i just find it absurdbly uncomfortable for me anatomically)
Hope this helps.