For Solaris I use heavily modified versions of:
In missions, I normally reserve three for my personal use, a Hellhound, Timber Wolf and a Dire Wolf, and sometimes a Mad Cat Mk II. The Hellhound I replace the ER Large Lasers with ER Mediums, making it run cooler and freeing up tonnage for extra ammo. For my Timber Wolf I drop the MG arrays, empty one arm, and place a ER-PPC in the other, then use the dud arm as a shield, with extra armor on it to boot. The Dire Wolf carries twin Ultra AC-20 (100 rounds each), four ER Smalls, and a LRM-15/SSRM6 rack. The Mk II is usually stock.
For all purpose ... I'd say the Puma for light. She has three slot spaces in bother arms, which are Omni racks to boot, letting her really switch her load out. She's not normally fast, but tonnage to engines solves that, while she can't jump, she makes up for it in her wide array of available weaponry.
Medium, I agree with you on the Uziel. Fast, versatile, can jump, respectable turn speed. I just dislike its reliance on energy weapons. I'd put the Shadow Cat here with it. Plenty of space for weapons, and the Cat can still move, though it is more fragile.
On the heavy front, I think the three Clan ones, the Summoner, Hellbringer and the Timber Wolf, are evenly matched, though the Summoner pulls up slightly ahead in its ability to jump.
As for the big boys ... I think the Hauptmann wins. It moves faster than the Dire Wolf, for marginally less protection, and can generally equal it for guns. My favorite variant has a Heavy Gauss and ER-PPCs, backed up by a trio of ER Small Lasers and a Streak 6.