I've chosen and ordered my tripod head - an Arca-Swiss Monoball P0. I got it without a QR setup, planning to attach an RRS clamp - it's actually cheaper than the Arca clamp, and it's guaranteed to work with RRS plates. It looks like the Monoball is compatible with both - it clears the wing nut on the RRS, and it's narrow enough that the Gitzo reverse folds pretty well, if not completely.
The question now is Gitzo (either the four section 1545 or the five section 1555) vs. RRS (TQC 14) for the legs. I'm visiting Boston over the next few days, and can see both Gitzo legsets at at least one dealer there. Unfortunately, RRS has no dealers anywhere.
The Gitzo has several advantages, one of which I'm not sure really is an advantage. The certain advantages are that it's cheaper (any $700 travel tripod that counts as "cheaper" is a little bit ironic, but it's competing against a $850 travel tripod), and that it's a tiny bit lighter (0.1 lb lighter with the column than the RRS is WITHOUT the column). It also comes with a short column that probably takes off another 0.1 or 0.2 lb (it doesn't look like it's possible to dispense with the column entirely, which the RRS does support). The advantage I'm uncertain of is reverse folding - it certainly makes it more compact, but does it also increase the chances of collapse?
It seems like the big advantage of the RRS is sturdiness - the leg diameters are equivalent to a (significantly heavier) Gitzo Series 2. RRS boasts endlessly of this, but it seems like the new Gitzo Travelers with the Carbon eXact tubing have gotten close - the top tube of a pre-2015 Series 1 Traveler was 21.7mm, but the new one is 25.3mm, not that far off RRS' 28.7mm. I suspect that Carbon eXact is probably a close equivalent of the large diameter thin-wall tubing RRS has been using (and their comparisons are to Gitzo's older Carbon 6x tubing). RRS also uses anodized metal fittings instead of painted (I'm assuming Gitzo fittings are painted, because that's who RRS tends to compare against), which they claim is sturdier.
Has anyone used them both? Is RRS a meaningful step up over Gitzo? I've decided to go for one of the two, rather than the Gitzo clones from China and Taiwan (Feisol, Sirui, Benro, etc.), because the 1/4 turn locks, anti-twist mechanisms, dust sealing and light, sturdy tubing are all a big deal to me. I've had a few clones, and none of them hae leg locks I like. I've used Gitzos, and the locks are in another league (not all of what you pay for Gitzo or RRS is just the brand, although I'm sure they take advantage of it - if one of the manufacturers of $250 travel tripods decided to build a $450-$500 travel tripod, I'm sure they could get in Gitzo/RRS territory).
Dan