How much does it cost for you ? (shipping included)
Julio,
The price of my Tarptent DW Moment (one-person) was similar to that of the Dual Rainbow: USD 290 plus a few extras, plus USD 20 shipping to Canada.
Since then, the US Postal Service has jacked up its rates for parcels to Canada, so much so that I rarely get larger items from the States these days, even with the slightly-better exchange rates now in place.
A couple of observations on Tarptents, from my experience:
1) I've found them to be very well made and well designed. The DW Moment, for example, offers excellent space for weight, the best of any tent I've had.
2) If you expect to use the tent for tours longer than a few weeks, or if you're big and/or long, then I'd invest in the extra space. I'm about 1.8 metres tall, and 83-85 kg. My DW Moment is fine for me for tours of up to a month. For a longer period, I'd opt for something larger. An example: I met up with a French fellow on my two-week tour of Eastern Ontario earlier this month. He was using a larger 2-person tent (by Vaude, I think), as he was on a Vancouver-to-Newfoundland trip, nearly 3 months; and, he was taller than me, 1.86 metres.
3) I was doubtful about the Rainbow's single-wall construction, because of (i) condensation; and (ii) bugs. Both are problems where I live; neither was much of a problem on my monthlong trip in the Rocky Mtns and the Pacific Northwest last summer. You could handle bugs by buying the Rainbow's optional internal liner. I don't know about answers for condensation with the Rainbow. The DW Moment has very good ventilation from both ends, and ventilation is also aided by the internal liner, which allows me to open at least one side vestibule at night. Also bear in mind that with the Rainbow, you have to purchase the alu or carbon support poles. (Or use your own trekking poles.)
4) The one aspect of pitching the tent, which I have found is often fiddly, is this: My DW Moment uses a single hoop pole (similar to the Rainbow Dual, as I look at the photos of the Rainbow.) I have found it less-than-easy to thread the hoop pole quickly into its tube when pitching the tent; and also to take it out when taking the tent down. My hoop pole (anodized alu) binds on the tube, especially if the pole or the nylon fabric is damp, so that this single operation can take me a few minutes. Maybe a more spacious tube would help?
Hope that's helpful, and good luck.
John