Years ago I tried an Ennis and a Barcelona Filbert tree. After about 5 years of nothing - I gave one away and dropped a fir tree on the other.
Willamette Mission State Park (on the Willamette River) has a large once commercial filbert orchard. One fall day I and my Homeschooled kids made a trip to 'harvest them.' Before we picked up too many nuts, I decided to test a few. They were large and beautiful, Barcelona I presumed. But every single nut was empty! I think it's
Filbert Husk worm ... and I've been told they require a spray program to combat them ~
The best we can do around here are wild
Hazel nuts, and as mentioned above, attempt to beat the
Stellar Jays to them - which we can't

There are a couple of neighboring Filbert orchards we occasionally wonder into at 'that' time of the year ... the nuts are great at that pre-dried stage. But considering the obstacles, I no longer recommend Filbert yard trees. They sound like a great source of protein, but in practicality - they were duds. If you decide to give them a try, be careful to match pollinating varieties.
As far as looks, the catkins in February were pretty, but you either prune them to a single trunk like a 'tree,' or allow them to sprout into a 'clump' like figs do. We liked the
tree look, but perhaps production-wise ... that wasn't the best method?