Hello, Shane, and welcome to BackpackGearTest.org! This is an excellent first Owner Review, and with a few revisions many simply to conform to BGT protocols I expect to approve it for upload very quickly. I use BGT's standard notations for edits: EDIT (all caps) is a required change; Edit (initial cap) is a suggested change or request for clarification; and Comment is a comment, with no change required.
After revising, please repost the plain text of your OR to this list, with a link to the html version in the Tests/OR folder and "REPOST," the product name and your name in the subject line.
<<BY Shane Williams
EDIT: By (or by) no reason to capitalize this word
<<Location: Colorado Springs, Co>>
EDIT: Colorado Springs, Colorado USA [BGT has non-US readers who may not be familiar with the USPS abbreviations. And country is required.]
EDIT: There's nothing wrong with what's here, but we also need something about your backpacking style. How long is a typical trip? Are you traditional, lightweight, ultralight? What kind of shelter do you use? You've only used 75 words and can get some of this in while honoring the 100-word limit.
<<MSRP: MSRP not indicated. Average price: $19.95 US Dollars>>
EDIT: Delete the second sentence. The only pricing information allowed is what comes from the manufacturer on its website or a hangtag, say. There are several reasons for this, but it's a firm rule.
<< The unit markers are placed along the left side of the reservoir positioned at 0.5L/17oz, 1.0L/34oz, 1.5L/51oz, 2.0L/70oz.>>
EDIT: Do the markings have both liters and ounces, or only liters? If the former, put the latter in parentheses or brackets, or delete them. [Because bottles and bladders are universally sold with metric capacity, this is a rare instance in which a conversion isn't required.] If the latter this is OK subject to the next EDIT.
EDIT: Always use a space between the number and unit of measurement: e.g., 2 L. Fix this throughout your Review (including the title). Same for temperatures - 10 F not 10F.
<<The pour spout is constructed of a polyethylene material has screw on design.>>
EDIT: has a screw-on design [Add "a"; hyphen is optional.]
<<Trips: Mount Elbert (3/20/2010)>>
EDIT: Most places in the world (and in the USA too if you're in the military) the day comes first. Write out all dates: March 20, 2010. Fix the others similarly.
General EDIT on Field Conditions: Indicate where you stashed the Hoser in your pack (and if so in a sleeve). This helps the reader understand how you use it.
<<On an average day in the High Country I carry 4 Liters of water.>>
Edit: Single-digit numbers read better when written out four liters. That's up to you, though.
EDIT: liters [lower case L]
<< My Hydration system consists of 2 Platypus Bladders.>>
EDIT: Drop the capital letters on 'hydration' and 'bladder.' Save them for proper names and trademarks (see below).
<< The primary bladder is a mountable Platypus Hoser 2.0 Liter Hydration System for on the fly re-hydration. >>
Edit: on-the-fly [with hyphens]
Comment: Here upper case Hydration System is correct, as it's part of the product name.
<< First off, a few uses that you wouldn't expect from the standard hydration system:>>
Edit: BGT prohibits `projection' anything that someone other than the writer experiences, so we editors instantly pick up any use of the second person. It's OK here, but not usually. Consider changing to "I didn't expect."
<< water can be boiled and placed in the platypus.>>
EDIT: Platypus. All trademarks (brands) must be used exactly as their owners do. Upper case P. Here and several other places in your report.
<<it can be used as a heating pad in the event that the hike left sore muscle.>>
Edit: "a sore muscle" or "sore muscles" reads better
<<Keep it in a cooler while driving to the trail head.>>
EDIT: I keep it. [To avoid projection.]
Edit: "trailhead" is usually one word
<< Once on the trail, the frozen Platypus turns to water, cold water on a hot day is a welcomed treat.>>
Comment: Indeed it is.
<<On a winter trip in the Appalachian Mountains I noticed that my conventional water bottles had frozen solid, but the water in the platypus was still "slushy" and drinkable.>>
Edit/Comment: Might this have been due to where the containers were stored? You might explain that they were all in similar circumstances (in a tent vestibule, for example) so that it's a fair comparison.
<<The Platypus line of products are versatile and worth the money spent.>>
EDIT: is versatile ["line" takes a singular verb.]
EDIT: and in my opinion worth the money spent [projection again]
<<I would recommend this product to anyone looking for a Hydration System.>>
EDIT: hydration system [Lower case; you're not talking about the branded product.]
<< Recommended Accessories:
Closure Cap: Useful for capping reservoir.
Tube Insulator: An insulator that help keep the hose from freezing.>>
Edit/Comment: That cap is one of the best things about a Platypus converts a hydration bladder to a camp container. Consider further explanation.
EDIT: that helps keep [singular verb]
Comment: On mine it helps, but not enough!