RE: Is Vbar worth the added expense?
It all depends on what you want. The pros go beyond looks and flight time. Head speed is arguable but you do get slightly more available power or time due to the decreased resistance. You can use tis as you wish for longer flight time or more power during maneuvers or higher head speed if you were at the limit of your power train. But normally you should have sufficient power to hold your desired head speed even with a flybar so I think head speed is not a typical advantage.
The other advantages are increased reliability due to the elimination of many head parts. Reduced head slop. Lower repair and maintenance costs. You will see may post on this in various forums. I fly both and can attest to the improved reliability and lower cost as well as less time I send on the head mechanics and tracking. You head cost less as well and you do not need a seperate tail gyro with the 3 axis Fylbarless Stabilization Units (FSUs) available such as Mikado and SJGD if you are starting from scratch. IF you use a high end gyro this can be a significant savings.
But beyond this are flight characteristics. Flybarless controllers to some extent decouple stability and performance from the traditional physics and aerodynamics. Blade weight and stability is supplemented by gyros which add stability. So you could use a lower weight blade and the FSU would stabilize the copter. This could allow higher roll rates for 3D. Characteristics such as pitch-up in fast forward flight are typiclly compensated for by a FSU. A small copter like the 450 can be made more stable for the same reasons - gyros do the stabilization not just the physics.
This also means wind and gusts have less of an effect and can allow flying in conditions difficult for a flybarred copter. Again I was amazed at the gusty windy conditions I could fly in.
Another beefit is the ablity to tailor the flight characteristics to how you want to fly. You can go from scale type stability to sport to crazy 3D performance by altering the parameters. Of course the performance envelope of the copter is the limiting factor. You can't get water from a stone!
But in the end if you are happy with the flybarred setup you have you may not want to change. For me I can say it actually saves money. But I fly a lot. On the other hand costs are coming down. SJGD lowers the entry price for an advanced FSU.