Well, I have seen a lot of threads regarding the technology on the Destiny. A lot of people (who probably know very little about science in general) speculate that the Ancients were not at their prime, thus no hyperdrive and (relatively) primitive weapons.
Now, we recently PROVED the existance of Tachyons and the possibility to travel FASTER THAN LIGHT, despite Einstien's flawed relativity (does anyone remember how in the 1910s it was impossible to travel faster than the sound barrier?) theory.
Presumably the Ancients had made this discovery, and had serveral decades, if not centuries or even mellenia on this discovery. This then implies that they did, indeed, develop a method of faster than light travel through real space. This discovery MIGHT have come after they developed subspace drives. We will never know. Though please do keep in mind that Universe is set at least several years after the end of SGA.
Please remember post SG1 we have the ancient core drive, which presumably we have the technology, now, to replicate and make many times. This core drive includes ALL the knowledge of the asgard, and all its technology. Post SGA we have the ENTIRE Ancient database. Including the power requirements to contact the Destiny, its true mission, and how to manufacture ZPMs.
This makes the premise of SGU pointless, as is. However, this is neither here nor there. It stands to reason that the most likely method of FTL travel that the engines use is by enveloping the ship in a tachyon field, and propelling itself forward. It would be faster then Hyperdrive through inter-galaxy travel, but would be subject to gravitational eddies when within a galaxy, thus the reduced speed. It would also, theoretically, require less energy then phasing the entire ship out of real space through a hyperdrive engine.
This one really annoys me. A single drone weapon is not that hugely powerful. Swarms of them are. The fact that drone weapons do not have the same yield as a gigaton warhead implies the Ancients are not a warlike species.
Why do people then complain that the main weapon on the Destiny is not uber enough. Do you want the Death Star ray? Why? It contradicts everything we know about the Ancients (do remember, this is pre-ori). The main weapon, as we see, is actually a multitude of large yield plasma cannons. Enough to go head to head with the typical capital vessel of any war-like race, when 1v1, but not when swarmed (it takes only a 3 hits to destroy a Drone command ship after all). Then the Destiny is littered with point defence weapons. This implies that Destiny truely is a research vessel, armed with a weapon that would deter any attack, and smaller weapons to defend itself, but not armed to obliterate everything in its path with ruthless efficiency like a REAL Human capital ship would be.
This is all, for now. If anyone else has logical, scientific analysis of these systems, or others, please reply!