While the thumb strakes can interfere with ejection (usually interfering with the one cartridge directly it line with it), I've found that incorporating a slight cylinder twist and incorporating multiple activation of the ejector rod (usually 2 hits in rapid succession works) in the ejection process resolves that problem. The Safariland Comp II speedloaders designated for Ruger -Sixes won't work with the Trausch grips with the thumb strake-but the Safariland Comp IIs for S&W K-frame ones will. HKS speedloaders designated for the -Six Rugers, being slightly smaller, will work with the Trausch grips.
In my experience, the benefits of the Trausch grips (ergonomics, index, control, recoil absorption/dissipation) far outweigh the negatives (scarcity, need to modify to fit grip frame if a square-butt -Six, need to come up with a modified ejection technique). Obviously, your individual physique and experiences may differ from mine.
Best, Jon