I picked up both the P239 and Mosquito (both two tone versions) this past week and finally took both to the range today. Pics of the handguns to follow later. I cleaned and lubricated both guns prior to the range visit. I shot 200 rounds through each. The P239 was fed with Federal 115g FMJ and the Mosquito was fed a dose of CCI MiniMags.
First, the P239 was flawless. No malfunctions. Shot it at 21 and 33 feet and found it to be as accurate as my P226 Elite 9mm. (I did not take my P226 today to compare since I wanted to spend my time shooting the P239). This will be my carry piece and I was not disappointed in its performance. On my last target I opened up an inch wide hole just left of center with the last 2 magazines. My groupings were better at 7 yards than at 11 yards, but that was to be expected. I am very glad I got it.

Now the Mosquito: Since I have been disappointed with the accuracy and performance of the Walther P22 I wanted the Sig Mosquito for comparison. IMHO, 2 words: No contest. Hands down the Mosquito is much more accurate that the P22. YMMV. Out of 200 rounds of CCI's I only had two FTFeeds. I had no FTE's and the slide locked open every time on the last round. The size and weight of the Mosquito also simulates the larger caliber Sig's which I liked and may be why I am dissatisfied with the smaller, lighter weight P22. Also the magazine eject method of the Sig is by far superior to the P22.
If today's results were any indication, I will be putting my Walther P22 up for sale.

UPDATE: I took my P226 Elite back to the range along with the P239. Although I shot well with the P239 my P226 is just a tack driver. Bottom line I love them both.