I've bought two new bits recently. The purchase was prompted by the ruination of a neck I was routing for a stratocaster. The bit was decent, I had left no more than 1 mm to route having sanded it 99.5% of the way to the line, and I'm always super careful, but while routing around the heel across the endgrain, it STILL bucked, went bang, and split the neck into firewood.
So I finally bit the bullet and bought a couple carbide spiral flush trim bits and while the price tags made me absolutely cringe with horror, no sooner did I start using them and I forgot all about how much I paid (almost!)
I bought two different bits, one with a bottom bearing, and one with a top bearing.
If you can afford one or both of these bits without choking to death on the price, I highly recommend them.
I routed several maple Strat necks with the Freud bit and it ate them for lunch. From the way they cut you could feel no difference between long grain and end grain, and the finish it left felt like it had been cut flat with a razor sharp hand plane. This is now my go-to bit for those type of jobs.
The second bit (whiteside) did an equally amazing job trimming 1/4 rosewood boards. Felt like I wasnt even cutting anything, as well as routing around the perimeter of a VERY quilted maple top and it left and edge like glass with zero tear out. I've never routed quilted maple without some tearout before, so I was seriously impressed
The whiteside bit will also plunge and leave a glass smooth bottom on the cavity.
Anyway, just thought I'd throw in my 2 cents (lol) on these bits
First one (top bearing) is Whiteside Model UDP9112 Ultimate Spiral Pattern Bit
Second one is Freud 1/2" (Dia.) Flush Trim Upcut Spiral Bit