You do realize that a lower db number is a stronger signal, right? Everything else being equal, -70db is stronger than -73db. Each 3db is a doubling of the signal strength. Technically speaking, -70db is twice the signal strength of -73db.
So you saying that those with a lower db has trouble holding onto a 4g signal is the total opposite of what you should expect. For most consumer equipment, once you get above about -85db you shouldn't necessarily expect(but likely will still receive) good transfer rates or even be able to maintain a connection. Once you hit about -90 you shouldn't be expecting anything for connections. I did see a flip phone in the VZW store 2 weeks ago that was designed for -110 signal! I was impressed. Of course, it was a $200 dumb phone made by....Casio, of all companies.
If you really want to know that 2 phones CAN be compared apples to apples, look up their FCC IDs. If the RAZR M has the same radio characteristics as the RAZR, the paperwork for the RAZR M will basically say "this document is to indicate that the RAZR M uses the same radio as FCC ID: XXXX (RAZR) and is meant as a placeholder only". Then you KNOW you can compare them.
Other than that, trying to compare 2 phones even from the same manufacturer is really not logical at all. You'd notice the difference in measurement between yards and feet, and that's literally what you are comparing by just grabbing 2 random phones from the same manufacturer. Like I said before:
Look broseph, I'm not sure what your agenda is here, and maybe I should have used the word "weaker" rather than "lower" to refer to signal strength. But if you have a Razr M and a Razr Maxx sitting side by side, and the Razr M is both showing a weaker signal (i.e., -90 dBm on the M compared to -80 dBm on the Razr Maxx), that creates a presumption that the Razr M actually has a weaker signal. When you compound that with the fact that the Razr M also drops its 4G signal while the Razr Maxx does not, it creates a VERY strong presumption that the Razr M does indeed have a weaker signal than the Razr Maxx.
I completely agree with you that the "bars" of signal strength in the notification bar do not mean anything, but that's not what we are talking about. We are talking about the dBm signal strengths, and we are talking about actual dropped 4G signals.
If you seriously want to argue that a phone showing a weaker dBm signal strength that also drops 4G connections does not have a worse signal than a phone showing a stronger dBm signal strength and maintaining a steady 4G connection, well, I don't think anybody is going to convince you otherwise.