Strelky are 22 - 18MP to reinforce. Sturms low reinforce in 1.6 is an oversight/bug that was caused by the removal of the separate Sturm unit and changing it to an Ingenery upgrade.
Sturms lack Sprint and (with Urban) nades, so they won't be as strong against MGs. However, they have Satchels so are excellent against bunkers and Flaks/Paks. Strelky also gain some limited AT ability in 1.7, which Sturms lack completely. Basically, both units are pretty similar and it's all about what you need them for. Against just volks or grens, both will perform similarly.