No experience, but...
Titanium frames are sensitive to the welds getting contaminated during the weld process, either through pre-weld contamination such as greasy fingerprints or something, or via a brief break in the inert gas shielding allowing air to reach the hot metal. If the weld gets contaminated, it will crack and break in due course, which could be 2 or 3 years down the line.
Look at guarantee/warranty terms, for recommendations from people who've had a frame a decent amount of time (> 2 years or 15000 miles), and for the lack of "my frame broke" feedback. Feedback from people who've only had the bike a month doesn't really tell you much more than the pictures on the website. If Watly have only been selling direct under their own name for a relatively short period, you may just have to take a chance.
When ordering, the drawings are everything. If you receive a bike and it matches the drawings, but isn't what you expected, you've no come back; you should have checked the drawings more carefully. This is pretty much inevitable when ordering something custom made from the other side of the world.
