Prerequisites: vegan and reasonably easy to buy in or with shipping to Sydney.
1. Price per unit of actual protein.
2. Amino profile (about balanced or ideally slightly in favor of Lysine, Glutamine, Tyrosine, Tryptophan, Leucine, Isoleucine, in that order of preference/interest)
3. Free from dubious "diet" sweeteners like fructose powder, stevia, xylitol, manitol, sucralose, aspartame, etc.
4. Speed of absorption (would be very interesting, but is not critical)
5. Relatively unusual protein source(s) as I figure consuming a range of different proteins structures, while maybe not necessary, probably does more harm than good, if anything (for digestion, and for health).
6. Easy to mix into foods and drinks
7. Pleasant-ish or fairly neutral taste
8. Any other nutrients/benefits (need to be checkable/scientifically credible, and if you have to work hard to add them in, figure the value created will likely be lower than the value of the flexibility to do so myself, my way)
9. Preferably soy free / low or no isoflavone content. Even legume free altogether would be interesting for variety, since I already have heaps of legumes plus cheap pea protein in my diet.
My use case is for a fast sport, requiring mental and physical speed/responsiveness under pressure, some explosive power, and mostly agility. Power to weight ratio / reasonably low body weight is important, but second to peak rapid/instantaneous power generation and speed (hence I use creatine*, where probably endurance athletes, for example, would tend not to use it). For me, general health is also fairly important, for contribution to those performance goals, to train/play and continue improving for longer, and for life in general. Nutritional context: ~4000kcal diet (sometimes more), try to mostly use natural foods as much as practical and affordable, but supplement for any nutrients likely to support health, performance or both.
*some product manufacturers add creatine to varios other products. I'm not sure this is a good idea (limits use contexts according to creatine protocol) but it's not a total deal breaker unless it's old school non-micronised creatine monohydrate (micronised monohydrate, EE, etc are ok, within sensible dosing ranges)
I would happily look at any niche product up to $50-100 per kg protein for additional use/small occasional amounts (based on how well it meets most of those criteria), but most likely only as a secondary supplement unless price/value is in a similar ball-park to pea protein isolate ($20/kg) or protein/lysine dense cheap vegan foods (legumes, oats and wheat germ).
As examples, I do currently use/purchase:
* Nutritional yeast $50/kg / 50% protein = $100/prot.kg. Intake varies (small amounts on food). Benefits: tastes great, good source of B vitamins and B12, high protein content. Downsides: very low protein quality, too much added B vitamins for large scale consumption, pricey.
* Chia seeds ~ $20/kg / 20% protein = $125/prot.kg. I mix a small amount with juice approx daily or occasionally mix with coconut cream plus vanilla soy milk + vegan vit D spray as a nice and very nutritive cold soaked desert. Considering price and amino profile, I only use this for the texture and the omega3 content, both of which are quite nice.
* Brewers yeast $30/kg / 45% protein = $65/prot.kg. Hardly use, as amino profile is not that great, and the only way I've found that I like the taste is very small amounts mixed in miso soup (which then means high sodium as well as high B vitamins). Nutritional yeast seams to be worth the extra 50% in price.
* Spirulina $50/kg / 65% protein = $75/prot.kg. About 10g/day average. Considering swapping some/all for Chlorella. There seem to be some wild claims out there about these products, but also some good genuine nutrients that I like to get. Much better protein quality, but still doesn't come out at all good on a value by lysine matrix chart.
* Have tried plantfusion (interesting because of the different protein sources, reasonable amino profile and reasonably priced, but not cheap). I rarely use it now, and will likely never re-purchase, this product. It violates points 3, 6 and 7 on my wish list and doesn't seem to have enough unique benefits to make up for this.
* Considering maybe trying that sacha inchi stuff but didn't get around to looking at how to order it.
* Considering trying hemp products but concerned about the possibility, however remote, of cannabinoid contamination, i.e. technical doping connotations, plus have not seen any availability for cheap in Australia.