I started to take your advice, but could not resist commenting.
The problem is I am opinionated about the question so I will try to give a un-opinionated response.
First, there are some very good pre-made rifles that will shoot very well, and with some careful research you can find a good one. If I were going to buy a pre-made rifle I would first look at the guys on this site like Len for one because they understand the needs of our sport and have a reputation to look out for with the membership.
Lots of builders require that you pay for testing of there preferred loading and offer no accuracy guaranty if you shoot/load any other load that there's. This is one of the issues that I have with these rifles because a well made rifle will/should shoot every load well and when you find the right load it will be scary accurate.
Going the custom build has many advantages in my opinion if you pick the right smith that wants to build you something special and has the skills to do so. They are out there if you look and talk to them and explain what you want and expect.
When finished, a custom built rifle should be one of a kind, exactly what you wanted, and the build should be a lot of fun and satisfaction. In the end, your chances of owning a real nail driver should be better, and cost might even be less because you are not paying for a name, just quality. Its kind of like having a baby, You should enjoy making it and have complete control of its quality and performance if it is treated/raised right.
Building one with the right smith can also a 'good' learning experience if the right smith is picked.
J E CUSTOM
Jerry,
You're no where near opinionated and one of the few folks here that I look up to and your response is a prime example why.
Cheers!
Ed