Sorry, no experience with the Silca.

I've used the Lenzyne Road Drive, on our tandem (32 mm tires pumped to 110 psi). I actually like the screw-on head, it feels very secure and with the little flexible tube you can really push on the pump without worrying about damaging the valve. I didn't have any problem with unscrewing the valve core, but I'll keep an eye on that in the future. It took a while to pump our tire up, and yes, the pump did get warm (not a problem when you have padded cycling gloves). As with any pump, the last strokes were hard, but I was able to get the tire up to pressure pretty quickly and easily. I like the Lenzyne about as well as my Topeak Roadmorph, which is larger and takes fewer strokes to fill a tire.