I started using Bosch bits on my first couple of projects but have moved on to both Freud and Whiteside, depending on the bit and availability.
For my roundover bits I prefer the Freud quad cutters. For cutting and flush trimming I prefer spiral over straight bits.
Carbide is a must. HSS is a waste of money. They dull way to quickly.
While a set is a good way to get started, once you have to replace a bit, spend the money and get a good one. Buying a lot of high quality bits at once can be expensive but getting them one at a time as you need to replace something is a lot more reasonable. Like a lot of things, with router bits you get what you pay for.
When you are using a bit with a bearing, make sure the bearing is secure before you start, need I say more?
I cut most of my recesses and driver through holes with a 1/2" spiral upcut bit with a 1/2" shank. This works fine with my Jasper jigs, I just have to adjust the pin hole used to account for the larger diameter bit.
My flush trim bit for use with MDF or Baltic Birch Ply is a 1/2" spiral with a 1/2" shank. For trimming veneer from through holes I use a 1/4" spiral flush trim bit with a 1/4" shank in my trim (laminate / Bosch Colt) router.
For trimming veneer from the recess of a driver hole I use a Whiteside small pilot flush dado cut (Part# SC28C). This works very well but needs a light touch since it does not have a bearing.
Don't try to hog out a lot of material at one time. A little at a time will give you much better results and will also reduce burning. When cutting a driver hole through 3/4" material I will usually make four passes. I step the depth down so the last pass only has to remove a very little material (~1/16").
When cutting through holes, make sure both the main piece and the scrap piece are securely fastened to your backer board, I find double stick tape (I use bowl turners tape) works well. If you do not have the scrap piece secured, when you cut through the bit can wander and cut a gouge in the baffle

Like others have said, keep you bits clean. I also like to spray a dry lube on them before I start cutting.
Mike