This review is by Steve Thomas who is closely connected with the manufacturer. You should read his disclaimer

The XTC X-10

Manufacturer:
Buena Vista Kite Company
301 8th Street
Suite 207D
San Francisco, CA  94103
415-626-3599 / 415-626-1226 (FAX)

There are Three XTC X10's, here are their stats:

Product Name             Price*    Frame               Weight
Standard                 $290      Avia Excel          10 oz.
Ultralight               $320      Avia G-Force/UL     7 oz.
E-Vent                   $330      Avia G-Force        11 oz.

*U.S. Suggested Retail, "Street Price" will probably be
less.

All Kites:
Type: Dual-line dart-type, stand-offs, curved leading edge.
Dimensions: 118" wide, 44" tall
Graphic: 9 panel: two wings, split horizontally, diamond
          center, two triangle-shaped panels on top and
          bottom sides of diamond
Sailcloth: Icarex 1/2 oz., 3/4 oz.
Construction: Laser Cut panels, sail-taped seams
Wind Range: Standard: 2-18 MPH, XXL: Indoor-8 MPH,
            E-VENT: 10-35MPH

Review

The Kite.
The construction quality of all of the X10's is not only superb, it is
flawless.  Using a construction technique used by only a few manufacturers
in the world, the X10's quality and consistency will be noticed
immediately. 

Construction design of the X10's reflect three things: the refinement of a
very mature design; the influence of the very harsh Bay Area wind
conditions; and the needs of a "radical" competition flyer.  The X10's are
built *tough* for doing harsh, radical flying.  They are also built with
features like, "tangle free" fittings, and very *tight* vinyl so they
don't pop out even after a long time flying.  All models have advanced
features such as rubber-banded fittings securing the vinyls (again, with
the "hard core" competitor in mind).  The X10 has a "6 point" type bridal 
for maximum control and wind range.

Flying. The X10 has all the radical features of the eight foot XTC, but
but in a much more stable, slower platform.  There's not much I can't do
with the X10.  The X10 will double-axel, black-hole, side-slip, and stall
so solidly that you can practically throw your handles on the ground and
it will stay stalled; and it is so steady it looks like you painted the
kite in the sky! 

For a kite measuring about 10 feet in wingspan, the X10 is very, very
responsive--more responsive than many modern 8 foot wings I've flown. 
Like the rest of the Buena Vista line, responsivness is accomplished by
the overall design, a very stiff frame, stiff vinyls (made out of very
hard polypropylene or nylon not soft rubber or vinyl), and a very tight 
overall sail. 

Precision work with the X10 is excellent.  Tracking is slow and
deliberate, making the X-10 an excellent team kite (the choice for Team
Cyborg, Team VisionAire, etc.).  The standard kite has incredible wind
range--its excellent versatility in light wind belies it's rather heavy
weight.  This kite is extremely fun in 3-5 MPH of wind, where it can put
simply anywhere in the wind window, and slid to the left or the right (I
love to play with the X10 on board walks and the like). 

A Note About the Company.
Buena Vista Kite Company was founded in 1991 and is owned entirely by
Peter Werba (Peter is now a renown indoor flyer and innovator).  Buena
Vista sells kites in at least 50 kites stores all over the world, and is
one of the top selling kites (if not *the* top selling kite) in Japan. 

Buena Vista sells a complete line of high-performance sport kites ranging
from beginner kites (Streaker), to competition kites (XTC line), to
competition team kites (XTC X-10 line), to the two indoor products (XTC
Feather and X4I), and the newly released Cyborg VIII.  A total of 11
products in all. 

Buena Vista continues to be an innovator in high-performance flying, as
well as high quality sport kites.