A Beretta Model 3032 is my usual BUG. I'm going to agree that it's a lightweight, light-duty pistol with a limited service life; but, based on my experience using it, I'm going to say that the effective service life of a, 'Tomcat/Alleycat' is more like 2,500 to 3,500 rounds. I've had mine for a good 15 years now. The soft alloy frame is beat all to hell; and the anodized finish is severely worn; but that little gun still shoots quite well. (I'm going to guesstimate, about, 1,000 rounds have gone through it.)
It's a soft hitting gun - Really a soft hitting gun! The outstanding advantage to carrying a Model 3032 is that it's a very easy small pistol to transition down to from a standard full-size frame. Because of the Tomcat/Alleycat's wide backstrap it will grip very close to the full-size semiautomatic you just put down; and your POI will tend to remain the same. (My groups usually open up a little; but there's no significant loss of user accuracy due to quickly switching from a large pistol to a smaller one - THIS I really like about Beretta's Model 3032!)
Are you making a mistake? I don't know? Sometimes, when I need a lot of concealment and a very flat weapon-profile, I'll carry a Walther PPK-S in 9mm Kurz. The Walther is an entirely different gun and reflects a change in both purpose and feeling. Both pistols are blowback operated; BUT, the Walther really lets you know that it's a blowback design! The Walther hits (marginally) harder; but, at the same time, it feels like a small gun in your hand(s), and might throw your first several shots off. The Tomcat/Alleycat does NOT feel small in your hand; it simply IS SMALL; and, for me, my POI tends to change very little as I move from a bigger to a smaller pistol.
In the right hands both of these pistols are, at best, 16 to 18 yard weapons; both of them are light-hitting, 'minor calibers' - Really minor calibers that far too many Americans seem to be much too enamored with, right now. The German-made Walthers have always worked well, and are known to be highly reliable.
On the other hand, many of the Interarms-stamped Walthers - especially the pistols Interarms either assembled or manufactured, here, in the States - have poorly designed and/or fitted feed ramps; and none of these defective Walthers are ever going to be trouble-free. The same thing is, also, true of the early Smith & Wesson-stamped, Walther pistols. Both should be avoided. (An Interarms, East German manufactured pistol, like mine, can be flawless, and 100% trustworthy; but a non-German, Interarms/Alexandria, VA, Walther pistol should be avoided - Let someone else have the problems!)
As for the Manurhin (French/German) Walthers? As far as I know, they are well-regarded, perfectly reliable pistols with none of the inherent component or design flaws that have plagued many of the other Walther imports, or the early S&W designs. If your friend's Manurhin pistol is jamming, I can't tell you why; and I won't even venture to guess. If you decide to go ahead with this trade then I would suggest the following modifications: Change the existing recoil spring to one from Wolff Gunsprings. Buy a new Walther magazine. Use the original bullet these pistols were designed for: FMJ round nose! Because these are such light calibers I always carry FMJ/RN bullets for self-defense. (In any caliber as soft-hitting as one of these, penetration is always worth more than expansion.)
My personal opinion is that I don't see you, 'shooting craps' on this trade. Your Tomcat is, probably, going to last longer than you think, and generally look like hell, too. The Manurhin will be larger, bulkier, more substantial, and more difficult to conceal. It will, also, be a generally more useable pistol with a much longer useful lifespan. I'm just not sure how practical it is to evaluate small pistols like these in terms of, 'useful lifespan' or total number of shots? (Remember the duty-cycle on an expensive and, somewhat, more substantial Seecamp pistol is no different! Excluding the larger, heavier Walthers all of these lightweight, really small pistols are designed to conceal, easily, rather than to, 'last forever'.)
Me personally? I wouldn't be quick to get rid of my little Beretta. Its assets clearly outweigh its liabilities. It ain't pretty; and it's sure to get uglier with the passage of time; but, it does what I need it to do, and looks ain't everything!