Had this question asked on an RV forum I monitor. Thought I would share my answer.
While I don't have a Class-A, other than the length, I'm not sure if any one system is significantly better than another. As long as the system you buy can handle the total number of tires on your coach + toad AND is rated for your tire pressure. Warranty length and service may be the only meaningful difference between some units.
I have done what I think is the only direct real-life comparison of internal vs external system back in 2018 and published the results on my blog.
But some general observations and comments.
IMO User-replaceable batteries are a plus. You can confirm the battery P/N before purchase and check at a grocery store or at Home Depot or Lowes for both price & availability but most are under $2 each and last 1 to 2 years depending on use. I have found that after 8 to 18 months use, low battery power may contribute to the dropped signal. My solution is to mark the install month year date with Sharpie.
I do like a system with long (Lifetime?) warranty and one that actually has the dealer/distributor attend RV conventions as that means they have people that are not just selling "widgets" on Amazon and probably have a telephone, email, and website.
RE: Repeater. I have listened to the "sales-pitch" from a number of different vendors at FMCA Convention and most will ask about the type & length of coach and offer suggestion to get a repeater or not but I also note that some will offer to send a repeater for just the cost of the repeater if you discover you need one later. Others just include a repeater with all sales just ask and see what they say or offer.
Alarms going off. I have a blog post on how I set my TPMS and haven't had any false alarms with the TireTraker system I purchased in 2009 (I did upgrade to the TT500 in 2018 after I killed the original TT400 monitor by connecting the wrong charger to it. My error not TT)
I have found I do not need a power cord to the monitor on the dash as a single overnight charge is good for weeks of daytime use.
I do shut off the monitor each evening. In the morning I turn it on again and by the time I am done with my coffee all 6 sensors have sent in the baseline pressure so I get a fresh "cold" pressure reading just to keep an eye on things. Do not be confused with the time to establish a signal. As far as I know, sensors only send a signal once every 8 to 15 minutes to conserve battery life. They also will send a Low-Pressure warning within 2 to 4 seconds. Read the literature or ask the dealer to learn what your system timing is.
Maintenance: I do run a "test" every year to confirm the sensors are still reporting air loss in the first few seconds. The post also covers spare parts I keep on hand.