I use the resources by John Okell. I haven't seen Colloquial Burmese yet, and considering I have enough as it is, probably won't buy it. But I could check it out on Google books are something if you'd like my opinion of it.
Because the language can either be called Băma săgà or Myăma săgà. Either of which în it's spelling in romanization (seeing as the Myanmar fonts don't always like cooperating) would be a bit odd, so I settled on Myanmar.