Recently, Brick Tracks did a little bit of advertising and putting their money where their mouth is by sending out free samples to 100 individuals. Upon receipt, I opened the envelope and checked the contents. I happened to get a segment of R104 track. The finish is excellent and nearly identical to LEGO tracks. The color is a virtual match and the finish isn't as glossy, but it's not easy to tell the difference at 10 feet. The track has fully compatible studs and tubes on the underside allowing for proper mounting and ballasting with real LEGO. The only difference is the studs have "BT" molded into the top and "Brick Tracks" and the curve size on the underside. While judging from Brick Tracks online catalog, each varying curve radius is designed slightly differently so one can tell by looking at the top the differences, the underside information ensure you can always figure out which piece is what.
The attachment to regular LEGO is the same setup and a breeze. The clutch ability is firm and I didn't have any problems connecting the segment of R104 to switches, straight track, curves, or flexi track. Once connected, the rail profile is the exact same. Running trains over it was a breeze and I didn't encounter any problems running regular LEGO PF trains or my diesel SD70ACe MOC over it with full rakes of well cars, coal hoppers, or passenger consists.
In summary, I am pleased with Brick Track's product and eagerly await their other geometry options. If they start to do switches and crossovers, I'd be even happier.