Big difference between the 2/3 and the 3/4 IMO. I almost got the 2/3. I just don't have a creek that small anywhere. It can almost seem whippy with lighter line, where the 3/4 is really going to flex. I think you can really tell the Sintrix is stiffening up the glass near the but of the 2/3.
Had been thinking about getting a very short (6'ish) 2/3 wt for a while. Found a Sirrus 6' 2/3 at a pretty deep discount and so pulled the trigger. With the disclaimer that my one test casting session was pretty short, some thoughts/observations....
Things I Wish I Knew Before I Bought It: Grip is only 5 1/2" long. Unlikely to be a major issue for most, but if planning to backpack note that the tube is larger, both in length and diameter, than it needs to be for a 3 pc, 72" rod.
Where Built: China (I had mistakenly thought all Hardy rods were made in South Korea)
Build Quality: It was hard to get a good look given the plastic wrapping and a very large sticker, but the cork looked to have quite a bit of filler. Otherwise, the build quality looked quite good.
Casting: I tried the rod with a true-to-weight DT3 and a slightly heavy Rio Gold WF3. I didn't notice any significant difference between the two lines. I definitely agree with the comment above about the rod's action. The tip section, or at least the first 12-18", felt incredibly soft (the oft-used terms noodle and buggy whip came to mind). But the lower sections are incredibly stiff. It almost seems like the sections came from two different rods. To me, there is a very noticeable flex point/hinge when casting and the tip felt a bit sloppy, in terms of recovery--by no means the worst I've felt, but not as quick as some others. One nice thing about the rod, perhaps because of that very flexing tip, is that the rod loads well with just a few feet of line out. But I just didn't care for how it felt in my hand.
Final Verdict: I ended up returning the rod. As mentioned my casting session was short, but at the same time I've cast enough rods to know what I like and what I don't and I was pretty sure it wasn't a rod that I would have grown to love. And while I don't need to love a rod I'll only fish a couple of times a year, I didn't like it enough to keep it, even at the sale price. For me finding a 6'ish 2/3 wt has been difficult. In addition to the Sirrus, the other candidates that I'm aware of are a couple of CGRs, the Butterstick II, a Steffen, a Barclay Synthesis and a couple of Scott Fs. The latter three are just more than I'm prepared to spend for such a limited use rod. And I haven't liked any of the other CGRs or Butterstick IIs that I've handled. So I had hoped that the Sirrus might be a good middle ground approach, but ultimately decided it just wasn't a good compromise from a price-to-enjoyment perspective.
Of course YMMV.