The Traveller was my main wheel for 6 years. I did add a Jumbo flyer/bobbin so I could ply two full regular bobbins onto one jumbo bobbin.
In 2008, I started travelling quite a bit for work and wanted ... Needed ... a wheel to go with me. I bought a Kromski Sonata and it has now become my go-to wheel.
I still use the Traveller for plying and for art yarns. If it wasn't for the need of having to get a fold up wheel, I probably would still be spinning on just the Traveller.