Brake Questions.

Ok, I tried to use the search and I found it futile. I am about to recieve my new 29er and I have been thinking about a GB4 Handle or a T7. The uni is strictly for commuting to work and riding aorund town. I hear a lot about brakes and I know that most people use them for Muni, I am just wondering if someone could tell me how beneficial it would be to have a brake on a 29’er. What are the main advantages and dis advantages.
Second question. Can I use an old U brake, or should I got to the expence of having mounts welded on to mount a side pull. I have seen people who have used a mounting bracket for side pulls. How would I mount that to a frame that did not have that capacity in the first place. Thanks

Brakes are great if you run short cranks and go down steep hills alot. They save your legs the effort of backpedalling to keep your speed under control. A 29" is a lot easier to control than a 36" downhill, unless you’re running incredibly short cranks I wouldn’t bother. If you;re going to use it for some serious off-road then this might be an exception. Exactly what uni are you getting?

i put an old u-break on on my uni. just drilled a hole in the bottom of the stem. it does not have much stopping power but does help me keep in control when going down a steepish hill. i am planing to put some shorter cranks on and i would not dare to do that without the break.

I am not sure the maker of the uni but it is a generic 29’er. The crowns look very much like a Bedford crowns do, but I am sure that it isn’t a Bedford uni. I will be putting 125’s on and I don’t think that I would go much smaller. i haven’t riden it yet, but I know how my 24 felt with 127’s on and I am sure that the 29 will be just as scary in the beginning. Kingston is quite hilly, so I think I might opt for the brake. If I never use it, at least I have it. It’s better than a high speed UPD and wishing I had one.
The uni has a Viscount Saddle and looks like a Nimbus or Semcycle. Someone could help me out on that too.