I've been running VP Fitness for over a decade and our smoothie bar has gone through probably 15+ protein powder suppliers. The biggest lesson? **Processing temperature matters more than most realize.** Cold-processed whey keeps the protein structure intact--we switched to a cold-filtered isolate in 2019 and member feedback on recovery times improved noticeably within 8 weeks. **Mixability is the most underrated factor.** If your powder clumps or tastes chalky, you won't use it consistently--and consistency beats quality on paper every time. I personally test every powder we stock by shaking it in plain water (no blender). If it doesn't dissolve smooth in 10 seconds, it doesn't make our bar. Members who train 5-6x weekly need something they'll actually drink daily, not dread. **Artificial sweetener load is sneaky.** We had clients complaining about bloating until we realized some "clean" brands were packing 3-4 different sugar alcohols to mask taste. Now we only stock powders with one sweetener max (stevia or monk fruit). Track your gut response for 5-7 days--if you're gassy or cramping, it's probably not the protein source, it's the additives. For 2026 I'd grab **Naked Whey** if you want zero additives or **Ascent Native Fuel** if you want flavor without junk. Both pass my shake test and our members who switched saw zero digestive complaints over 90-day spans.