While the LA.25 often has about the same power as a Fox .35 stunt, it doesn't hold up to the old Fox .36 combat special based engines. In addition, I have seen a great deal of variability in LA.25's when they are used in events where they are pushed a little hard. For instance, in 75 mph speed limit combat, some easily make the speed limit, others never get there no matter what you do to them. I don't feel that they offer any advantage over some other easily available modern engines. On the other hand, if you aren't real interested in being competitive right off the bat, then any modern RC engine up to .40 size will be fine.
There is another thread that was recently done here that is in the same vein - asking for profile engine recommendations. The Thunder Tiger .36, the Webra .35 and the OS .32 are all mentioned. The thread starts at:
http://stunthanger.com/smf/index.php?topic=12513.0Here in our club, we have two profiles running on Magnum .36's - on mild fuel and with no modifications they are pretty good 'starter' engines. I feel that they have the potential to go real well, but haven't had the time or the inclination to put any effort into them. Contrary to other's experiences, we have had no trouble with the throttles, but one can't discount the experiences of some who have had.
As for Nostalgia, if you can get any of your dad's Foxes from 1973, you would get a bonus for a period engine.