25 vs 30 flap: From the operators side its five knots and a little longer landing roll. As a general rule 25 flaps will add about 2% to the landing distance as compared to a 30 flap landing.
The angle of attack is the same for both landings.
The best answer is which costs less. 25 flaps win. The get the check on maintenance, and fuel savings. 30 flaps only leads in landing distance and maybe gets the nod on brake savings.
Maybe the touch down point and how much energy is used at touch down is important.
Brakes: It is the old brakes, not the new carbon brakes. These old brakes heat up quick and are rather slow to cool. Most companies select auto brakes, min for normal landings, and med for wet runways, cause the brakes last longer and usually stay just a bit cooler. Thus cheaper to operate and maintain. Auto brakes look for a steady deceleraton rate and have a delay built into the application of several seconds in the min and med position.
Most companies also do not train on the best method for keeping the brakes cooler when using manual brakes. A good number of drivers love to make sure the brakes are going to work, so the make a jab at the peddles just after touchdown. This generates heat. Second a lot of drives think just holding minimum pressure on the brakes will keep them cool. Want to keep them cool with manual braking? Stay off the peddles till below 100 kts. Then come on nice and firm felling the decelleration in the straps. One application right down to taxi speed. When on the taxi way, stay off the brakes until you need to slow down and bring it right down to a slow taxi. Shut down exessive engines.
Auto brakes work great on most runways. The only real exception is hot day and long runway.... This of course is based on weight but at the weights near max landing a long runway would be anything above 3000m. At light weights say 220.0 kgs or less this could be 2500m.
This last point may touch a few egos. At weights when the runway becomes minimum, make sure to touch down at the planned point and let it touch with a nice solid bang. The solid bang eats at the energy thus needing less braking action and the touch down point gives you the runway length you need to stop. Grease jobs are not wanted when runway length is in question.
I always like flaps 30 and no brakes, I only get my way maybe 1 in 10.
Nuff said