My approach to this (and any gear) is to ask:
- What functionality am I after?
- What gear specs will give me that?
- What products have these specs?
With light rain pants there’s two general ways you can go functionally. You can opt for really light pants (3 – 4.5oz) with low denier fabrics and a thin membrane that will be good for occasional on trail use but not great bushwacking or for extended use, or you can opt for pants that are a bit heavier (5-7oz) that use tougher fabrics, thicker membranes and maybe 3 layer construction for extended durability and hopefully waterproofness. Obviously rain pants really exist on a continuum, but it’s worth thinking about what type of use you expect.
Examples of “occasional use rain pants” are the Montane Minimus, Montbell Versalite pants and departed favourite, the GoLite Reeds. All of these are 15-30D fabrics so they work fine on trail, but you can rip them pretty easily hopping logs. Typically these pants have quite thin membranes, so they can be waterproof when they’re new but that usually doesn’t last very long. The Reeds were an exception to this, because I think GoLite made them less breathable (I regret selling mine). For most really light pants, the combination of really thin membrane + high breathability (e.g. Montane Minimus) means they’re not likely to be waterproof for long. I used to own the Minimus pant and after 5-10 decent uses the water came right through (please don’t buy these or anything with Pertex Shield+). I don’t put any stock in HH ratings because lots of membranes seem to have high HH numbers but degrade really quickly because they were made super thin in futile pursuit of high breathability specs.
I don’t really value breathability at all any more. I’ve just been burned so many times that I now view rain gear as all being about the same. I’d much rather have waterproof rain gear that doesn’t really breathe, than more breathable gear where this rain comes right through. Sacrificing waterproofness to gain breathability never made much sense. Come to think of it, I don’t think I’ve ever owned anything WP/B that I found reliably waterproof after >2 years of regular use (although one eVent jacket did come close).
So anyways, preference is for a bit tougher rain gear but with the weight kept down via a minimal feature set and slim fit. Pockets, zippers and fly’s add weight and they’re extra spots for water to get in. After some looking, the best pants I could find are the Haglofs LIM Proof Pants. They’re 6.4oz and all the weight is in the fabric and waist band. They use tougher 40D fabrics, don’t promise sky high breathability and lack all features except a good looking waist band. I found a good deal on some for $67 (eBay link below, but most sizes are gone now).
http://www.haglofs.com/de/en/Pants/L-I-M-PROOF-PANT-MEN/p/602503.2C5
http://www.ebay.com/itm/291358335374?_trksid=p2057872.m2749.l2649&var=590517843148&ssPageName=STRK%3AMEBIDX%3AIT
My hope is that they’ll hold up for a while but my guess is they’ll probably last for a few years and then start leaking. For this reason my current preference is to buy Gore-Tex rain gear so I can warranty it when it inevitably leaks. I would have considered paying more for Haglofs higher end Gore-Tex take on light rain pants (LIM III pants), but they got to feature crazy with it (full length zips) so they’re 8oz. If someone made some Gore-Tex PacLite/Active pants with no features like the Haglofs LIM Proof pants I’d be interested. I’m in the market for a jacket and Haglofs LIM III Jacket