The plug-on neutral panels are a relatively new thing. To me, the main advantage is that it is a quicker, more straightforward install in that you don't have to separately run the pigtails for any GFCI and AFCI breakers in the panel.
I'd be inclined to say that they're going to perform as well as a conventional breaker. The conventional breaker "plugs on" to the hot bus and the plug-on neutral just adds a "plug on" to the neutral bus as well instead of requiring you to connect the pigtail to the neutral bus separately (screwing the pigtail to the neutral bus).
The main thing is that with today's code requirements for GFCI and AFCI protection, you're connecting more GFCI and/or AFCI breakers to the neutral bus. My house and workshop don't have any AFCI protection because they predate the code requirements for AFCI. I've been here for 30 years and the house has been here since about 1925 without issues, so I haven't gone to the trouble to update to AFCI protection. I have put in GFCI protection where needed by code (at the time) in the workshop and updated the house with GFCI to bath, kitchen, and exterior.
Here's my workshop panel and you can see four GFCI breakers in the center left of the panel with their pigtails. Those are for 15A circuits on the ground floor and at the time GFCI was only required for "readily accessible" receptacles in a garage where the floor was at or below grade. Since the 2008 NEC,
ALL garage 125-volt, single-phase, 15- and 20-amp receptacles where the floor is at or below grade are required to be GFCI protected.
This is a SquareD QO panel - I find them to be more robust and have more room than the Homeline version:
There is an argument that you can just put a GFCI receptacle as the first one in a circuit and all receptacles downstream from it are also protected and there is no need to use GFCI breakers, which saves you the cost of a GFCI breaker (GFCI receptacle = about $20; GFCI breaker = about $45). I chose to use GFCI breakers in my workshop because then everything was centrally located instead of having to remember where the GFCI receptacles are located throughout the shop - or that the receptacle ends up being behind something that has to be moved when it is tripped. Also, the QO panel has indicators that show when a breaker is tripped - so it is really easy to see which one needs attention. This means I can send someone else to the panel and they can easily find the tripped breaker too.
The red indicator shows up in the little window when it is tripped:
But for residential, it makes more sense to have a GFCI receptacle in the kitchen and the bath where it will save a trip to the breaker panel to reset a GFCI breaker.
As for what type of breakers you need and where you need them, much of it depends on the codes adopted by your State and local municipality. Looking at things, although Texas adopted the 2020 NEC effective as of 11/1/2020, the Texas Occupations Code § 1305.201 provides municipalities the authority to make local amendments to the NEC. So you'd have to check to see what is required locally for you. You'll need the proper GFCI and AFCI circuits as required by your local code to pass your electrical inspection. As for downsides, I'll address those independently.
GFCI's make sense in wet (or potentially wet) locations. They've been required on exterior receptacles, bathrooms, and garages (for garages - readily accessible receptacles with some exceptions) since the 1970s. The 1980s added kitchens (within six feet of a sink) and unfinished basements to the list. The 1990s added crawlspaces and wet bars. The 2000s added all kitchen countertop receptacles, the service to a dishwasher, and laundries as well as pretty much eliminating any exceptions for garages - including ceiling receptacles and those for garage door openers. There are a bunch of other specific requirements for swimming pools, hot tubs, boathouses, and other "wet" areas, but that is another discussion.
The one downside for me is the requirement for
ALL receptacles in basements and garages to be GFCI when you have something like a chest freezer or refrigerator there. Only countertop receptacles are required to be GFCI, so the kitchen refrigerator isn't required to be on a GFCI. If it trips and you don't notice it, you can end up losing $$$ in groceries. Other than that, a tripped GFCI is mostly just a nuisance but could similarly be an issue for anything you depend on to have constant power - security systems or a sump pump, for example - that may be in a "wet" location like an unfinished basement or garage. If an item is hard wired it doesn't need to be GFCI protected, which is the easy way to get around GFCI protection for a sump pump and still meet code.
AFCIs started out being required for bedroom receptacles in 2002 (by the 1999 NEC). The 2002 NEC upped that to
ALL connections in bedrooms (lighting, ceiling fans, wired smoke alarm, etc). In 2008 the NEC upped that to also include "family rooms, dining rooms, living rooms, parlors, libraries, dens, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas." So, pretty much everything except those locations where a GFCI is required. They also required the updated combination AFCI (CAFCI). The original AFCI detected parallel arcing (hot-to-neutral or an arc to ground). The CAFCI detects parallel as well as series (between a small gap or frayed area in the same wire) arcing. For this discussion, I'm using AFCI as a general term to include both AFCI and CAFCI (whichever one is required) unless specifically relating to one or the other.
As for downsides to AFCIs, the one issue I hear a lot of is that AFCI breakers (or receptacles) will trip with motor loads - vacuums, garage door openers, power tools, and such. If you think about it, you're naturally going to get an arc in a motor - which AFCI will likely detect and CAFCI will certainly detect. I see people say it is mostly an issue with loads over 5A, but that is pretty low if you're a DIY type person and apt to use power tools throughout the house - not to mention vacuums. Looking at internet discussions, of course you have the people who say they've never had an issue on one side and on the other side are the ones who have swapped out all their AFCIs and curse them loudly because of constant problems. Similar to my comments about GFCI protection of items needing constant power, having a AFCI trip and not noticing it can obviously cause you issues. It's something you'll have to decide for yourself - protect from the chance of an electrical fire or run the risk of not having constant power to something if the protection trips.
This is probably a lot more than you wanted to know, but I hope it answers your questions. I'll also say that I'm not a licensed electrician, so I may have missed some things or not explained them exactly correctly.