Choosing substrate

[Killfrenzy]

Mostly I'm looking for something that'll work for both plants and small loaches.

I've liked what I've seen from Onyx sand so far, but its buffering capacity does not seem to be as, ahem, "slight" as the packaging would suggest (indeed, I rather suspect Onyx / Onyx Sand are exactly the same as the gray Calcite from Seachem), so I doubt that's the best idea ever for loaches. It's also a bit coarse, but on that note...

I'm pretty much down to looking at Flourite vs Eco-Complete. I've seen people mention using one or the other here (yay search function), but I'm still slightly concerned about the texture of both(Eco-Complete not needing extensive, repeated washings is also appealing, but that's just a slight bonus, if anything).
Flourite I am currently using (got a half bag left here) and I rather like it so far, but it seems to compact rather well and I find that it is a bit on the... pointy side.
Eco-Complete I have no experience with aside from looking at unopened bags. I can see the overall round shape of the individual grains, which I am thinking is good. However, the texture, based on the bag's mention of high porosity, and its appearance (the way it looks, feels and sounds as it shifts around inside the bag) is also suggestive of a very fine pumice. Of course, keep in mind that these are observations of an unopened bag - I am not going to whip out a razor and slash open a bag full of water and gravel in the middle of a store (even if I did pay for it beforehand). So, can people who actually do use the stuff confirm or deny my current observations of Eco-Complete? I am considering trying it, but I'd like greater certainty before I shell out $20.

Also, for people who use one or the other in a tank with loaches (especially small loaches), how well does it work out? Does either ever cause any sort of scraping or barbel/eye damage?

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Addendum: Of course, I know about sand, and have a few spare carryout soup containers full of it here, but sand bothers me. I do intend to add some in deep bowls sunk into the substrate, in an attempt to keep it at least somewhat contained (I am planning on just small loaches for now, after all), but I have no plans on making it the main substrate or an integrated part of the main substrate.

EDIT: Hahaha, oh wow, I'm tldr

EDIT 2: ANOTHER QUESTION! Pond plant soil, anyone ever try that in a tank before? Sounds messy, of course, but still...