ORIGINAL: cutaway
I've never seen a Brodak in person.
Almost any modern .25 will struggle turning a 10x6 or 10x5 the old Fox's have no problem with (exception might be the Enya .25D diesel). Depending on the plane you intend to fly it in, a faster spinning .25 turning a 8" or 9" prop isn't going to perform as well as something that can turn a 10" prop. The Fox .35 weighs only 6.5 oz (minus muffler) too. Some of the newer BB .25's are closer to 8oz.
So far, the only Brodak engine that I've seen is my own 40. It seems to be a decent engine; whether that means the 15 & 25 are as good isn't clear to me.
I do have a sizable number of Asian Rim 25s I collected from eBay when first experiementing with power choices for the Speed Limit CLCombat events, and as already noted, the LA 25 is on the puny side of the power range, while the SF and FX are outstanding engines, and the FP is a fine middle of the class choice. The Magnum 25 is another good one, although slightly heavy for the class. In most cases, they swing 9-4s very well at steady speeds that work well for CL sport and stunt flying (I use 8-3s and 8-4s for SL combat).
The only proviso with any of those I've played around with, is that the OS Schneurle 25s need the same high oil content fuels that the 35s and 40s do, to control a tendency to wind up under certain circumstances (the LAs do not seem to do that, but it's because the boost port in the cylinder sleeve was omitted, almost certainly, which is also why they are down on power at the top end of the rpm range). With a 9-4, and an oily fuel, the FP 25 has a power surplus that overmatches the old Fox 35 Stunt engine, no matter what prop you try to use on that one.
In the past, I have also substituted the Series 200 Veco 19 for a Fox 35 on sport type and smaller stunt models (up to the Sig Twister's size) with good results, also using 9-4s, but that engine worked quite well with 10-4s as well. I wouldn't rate its power output any higher than the Fox Stunt 35, but it is easier for me to needle than I've felt that a Fox is.
Although I own a few of the OSMax FP 20 engines that some west coast CL people are so very fond of, and go on and on about the virtues of, my own personal experience with them has been that they seem very picky about the fuel tank you try to use when they are mounted sideways on a profile model (although I may try one with a bladder for a newer Super-Slow SL event), and the 25s are much less persnickety with hard tanks, anyway.