There are some pretty good single mode diodes, but an ideal Gaussian beam is hard to beat, very true.
However as the OP asked about a choice between 2 of our common, what I call ( Level 1 ) divergence diodes I offer the 7875 as a better choice for a ( Level 1 ) divergence diode, as far as power, the osram is slightly tighter but not by all that much.
If OP is looking for beam quality then a DPSS is much better, if color without concern for beam quality beyond the original mentioned diodes then M-462 or NDB7675.
Of the 2 OP asked about I say do a search and read, they are close, but for that divergence and those MM diodes why not get a 7875 ?
My answer to yours , is not whats better I just prefer the PLTB450B diode. I built plenty with it . Divergence is up to you, but it still has a great beam profile. G2 for power 3element for divergence ..