If your looking for servos similar to the Hitec 725BB Drum, the only other's I'm aware of currently in production are:

Futaba 5801 (available at just about any online hobby shop)

The following servos are more complex, larger in size, faster, and more sophisticated,

RMG Smartwinch 280, about the same power, but much faster with better resolution. Computer controlled and programmable, they also offer a 380 which is a huge step up in power.

U.S distributor
www.gbmy.com

Direct for RMG in Australia:
RMG Smartwinch

Whirlwind Winches; a little bigger than the RMG,and more powerful, but not computerized. The biggest will pull tree stumps.
Made in the U.K.
http://www.whirlwindwinches.co.uk/

And finally, Graupner Regatta 1, 2 and ECO. Not available in the U.S., but can be found on German Hobby shop sites, and may be available in EU or in the UK. Sorry no links. I did inquire with Horizon Hobby about special ordering one as they are Graupner's U.S. Distributor. Cost was exhorbinant, and item was not returnable.

One last source, check EBAY, occasionally the older Futaba S10 and S14 winches come up. (I manged to win the auction for one about a year ago). These were made up to the early 90's. Excellent winches with metal gear trains. Considered bullet proof. THe S10 is a little weaker than the Hitec, the S14 more powerful. The are heavy at close to 8 ounces, but are highly desired by EC12 sailors for their reliabilty and resolution.

As to servo comparisons for the 525, check this sight:

Servo Comparison Chart

Hope this is the info your looking for.

Chris