This is going to be a really long post, so I apologize in advance, with the caveat that I hope it answers all your questions.
Currently using Marquette and have been for three years, including two rounds of postpartum NFP. We used STM prior to our first kid.
Standard I-am-not-an-NFP-instructor-please-don’t-treat-this-post-as-comprehensive-NFP-education disclaimer here.
First off, I agree with another poster who suggested telling your doctor about your temps. As I recall, low post-ovulatory body temperature can be a sign of an underfunctioning thyroid–might be nothing, but if your thyroid is acting up, then it can cause other health problems, and a simple blood test can find that issue.
Secondly, I find Marquette extremely easy. I particularly like that the primary sign (ie, testing) is completely objective: there’s no fuzziness about “is this mucus slightly stretchy or not?”. For my personality, it’s a GREAT fit. (Mucus-based methods work great for others, and that’s totally fine, of course! Just not a good fit for me.) After the first 2-3 cycles, the monitor will have learned your cycles well enough to have you use ten test sticks per cycle on average. I watch Amazon sales like a hawk and get boxes at $30/each or less, stocking up on a couple of boxes at a time, so that the cost is about $10/month. Worth every penny and more.
Someone above mentioned not charting. If you need to avoid, that could mess with your plans. The monitor may not give sufficient warning of ovulation alone, so in Marquette, you use an algorithm–earliest day of ovulation for the last six months minus six days
and unless you get a High reading on the monitor–to determine the end of Phase I. Past cycle information, then, is really useful for Phase I, if you plan on utilizing it. However, charting isn’t at all laborious. I note the monitor’s daily reading plus my interpretation of mucus and if we had sex that day on my chart–that’s it.
When we avoid, it’s due to serious health reasons, so we really, REALLY need to. It’s been successful for us thus far in both avoiding and achieving.
If you are on Facebook, there’s a really excellent Marquette NFP group that I can highly recommend. All the latest protocols get posted on there, along with new research and information. Perhaps the biggest downside to Marquette is that it’s not very well funded. Their website is out of date, though the charts they have for you to print are still correct, and ditto all of their non-postpartum information. The group has a lot of instructors who are willing to help a little for free, and whom you can contact to meet either face-to-face or via Skype for more information. All Marquette instructors, incidentally, must be health care professionals with a minimum of a BSN (bachelor of science in nursing) or its equivalent.
In terms of comparison to STM: I prefer it. No worries about disturbed nights=bad temps, no worrying about if I interpreted mucus wrong. There is also the fact that the culture in Marquette circles is more academic and straightforward than in other methods I have encountered, and I personally really like that. In Marquette circles, you’ll find people who also use temps to confirm. Or Creighton mucus charting. Or Billings. Or some combination of all of the above. And, well, no one cares, much less the instructors. It’s NFP. Unlike one or two other methods with which I have passing familiarity, there’s a strong culture of “if you need to use NFP, figure out what combination of testing/symptom observation works for you and your family, and do that,” rather than “if our method doesn’t work well for you at a given time, there’s something wrong with you,” which is an attitude I’ve encountered elsewhere.
One last thing: I spend $20 to buy a box of cheap ovulation predictor sticks every year. I use these as an additional backup: when I start seeing fertile mucus, I use the OPKs in the evening to double-check the monitor, and also in case the monitor misses ovulation. The monitor has missed ovulation exactly once in my three years of using it, but I like to be careful. (See: serious health reasons to space kids.)
I do apologize for the novel, but I hope it helps!