thank you for the post; as you say, there are several other threads on this topic, and what I see is that there is no hard-and-fast rule in choosing a broker. Did you read the relevant section of BabyPips school on the matter?
If you based your selection of a broker on their spreads, you would better be staying with Oanda because their spreads, by and large, are not that different from what one could expect in normal conditions; I hope that you are not judging their spreads by early morning standards or during news events… I would, if I were you, look at spreads during, say, Tuesday to Thursday, 9 - 11am Eastern Time (= 2 - 5pm London (GMT) time), because during greater liquidity you should have spreads around 2 to 3 pips for the Majors, outwith high-impact news release times.
I am with FXCM, for example, and what I value is their dedicated customer service values, which is as important as good spreads and execution speed: they have always replied to my queries and especially the FXCM thread on BabyPips saw all of my queries answered in great detail by the dedicated FXCM employee, Jason Rogers.
It also depends which currencies you trade: Majors, crosses, exotics… Spreads are never going to be an even playing field…
Good luck anyway!