Thought I'd share few thoughts on some of the
ink samples I've had a chance to try thus far. The photos are of swabs I made for my own use, on paper that's really too thin for such purposes and therefore went all curly, and I make no promises as to the accuracy of the colors...
Diamine Majestic Blue:
Ooh, I like this. It's a medium-to-dark blue with a certain depth to it, and on some paper (most notably the Staples bagasse paper I use for work and in my "sketch book"), it has a fascinating red-purple sheen at certain angles. I don't have anything else that's really close to this. Lovely, creamy, gorgeous stuff. Downside: it can be tempting to spend meetings endlessly flipping my notepad around trying to make that red pop out.
Lamy Blue/Black:
This ink is vaguely interesting, but not really much more than that. It has a little bit of iron gall content, so it goes down a pale slightly slatey blue and gradually (overnight or longer) changes to a greyer shade as the iron gall content oxidizes. It's an antiquey sort of color. Apparently
Lamy is changing the composition of this bottled ink and will soon cease making it in its current iteration...so even that slightly interesting aspect will soon be gone. Not really on my buy list.
Private Reserve Electric DC Blue:
Very bright true blue. In theory, it has some reddish highlights a la Diamine Majestic, but they are far less pronounced. It's a truly lovely color, but like many other PR inks (in my personal experience), it is something of a drama queen. It takes a long time to dry. It smears when "dry." It is a pain in the neck to rinse out of a pen. I love Private Reserve inks for their vivid colors and their smoothness, I really, really do...but this ink just reminds me I should probably sell off or give away the bottles of PR I already have, because they annoy me enough that I don't use 'em. I bought a small lot of them from a poster on FPN a few years ago, and despite the lovely shades, they've barely been touched. I have little tolerance for emotional ink. Plus they don't have any water resistance or other such qualities to make you overlook their bad sides.

(And now that I've just bashed them up one side and down the other...if anyone has an interest in PR Midnight Blues, Black Magic Blue, Fiesta Red, Sherwood Green, Avacado [sic], or Lake Placid Blue, drop me a note back channel and maybe we can work something out.)
Noodler's Zhivago:
I've been curious about this ink for years now, but it varies enough in reviews I've seen that I felt like I really needed to see it in person before committing to a big bottle. It's an odd sort of color: either almost-but-not-quite-black, or a very dark green tending toward olive, depending on the pen and paper. In most pens, it's a grey-green-tinted off-black. It interests me, and it'd be really cool if I could trade PR inks for some... I want some eventually, for sure. I also love the name! Tragic and bleak and depressing though it is in so many ways, I really like
Doctor Zhivago.
Diamine Syrah:
Nice. It's a lovely rose pink color with some shading, and it is silky smooth. However, it's somewhat similar to Noodler's Black Swan in Australian Roses, of which I own a whole bottle, and which has a "bulletproof" component that won't wash away in water or fade with time. I'd say Syrah is more ruby and BSiAR is more raspberry, but they're at least in the same family, and I don't really need both. But it's pretty! Recommended.
Diamine Oxblood:
This is another interesting color, and one that I could not for the life of me capture with camera or scanner. (You can tell how much I tweaked this one, trying to get it right.) It really looks like its name, which is...fascinating but perhaps a bit icky. Ever bought meat at a butcher's counter? You know those stains all down the front of his apron, or the stains you see on the paper your hamburger comes wrapped in? That's what this looks like. Not only that, but as it comes out of the pen, it's a fairly bright red, and then it *dries* to that rusty brown-purple oxblood color. Ew? And yet, it's a very attractive shade.

So far, I'm most tempted by Zhivago; and by Diamine Majestic Blue just because it's like nothing else I own and because it performs beautifully. And the Oxblood is on the "maybe someday" list. But overall, I'm not coming out of this wanting to buy full bottles of most of this stuff. For one, my archival paranoia keeps flaring up--I more or less trust the Noodler's Black because even the oldest journal entries made with my first bottle of the stuff remain unchanged, unlike every other ink I was using at the time (the difference between Quink Black and Noodler's Black is particularly striking). Many of the other Noodler's colors have a similar durability--some portion of the color may fade with time or wash away if they get wet, but they have a core that remains no matter what. I don't trust most other fountain pen inks for anything but day to day notes and drafts, and to an extent it annoys me to have pens filled with inks I can only use for certain purposes. I'd rather have inks I can count on through thick and thin.

Gratuitous shot of my favorite ink, just 'cause. See all the subtleties going on in there? Oh, I love this stuff...
It has been fun satisfying my curiosity about lots of "I think I like it, but..." sorts of colors. I'd saved up a number of them over the years. And it's fun just playing a bit with inks outside my norm, without any long-term strings attached. But when it comes right down to it, I'm liable to fall back into my Noodler's ways, and in my heart-of-hearts I prefer conservative colors for most writing: dark blues and blacks and browns...maybe green now and again. Having a few different colors/shades in circulation is nice--I like to alternate so I can see where one day or one writing session ended and another began. But I don't need a ton of inks to do that. And while brighter colors are fun, if I'm spending more time thinking about the color of my ink instead of getting down to business, there's something wrong. I'll make an exception for Black Swan in Australian Roses. It's just that pretty. And hey, you need a contrasting color or two for editing or off-days, no?

Black Swan and Syrah together--not the same by any means, but sort of cousins.