1) Like was said, it depends on the method of travel. Space travel in EVE is a bit different from most other Sci-Fi. Starships use warp-drives to get around WITHIN solar systems, but the drives require lots of power and are generally tuned to be as fast as physically possible. Warp speeds in EVE are pretty ridiculous, with ships like Interceptors having a base speed of 8.0 AU/s (Astronomical units - 1 AU = about 150,000,000 km, the average distance between the earth and the sun. 1 AU per second is about 500 times the speed of light, and every vessel travels at least twice that speed).
Like i said, it's used to get around fast within the confines of a system. Travel between systems is instantaneous, facilitated through Stargates. Stargates work in pairs, linking two systems, and create a wormhole bridging the two when activated, shunting vessels instantly between systems. Of course, the stargates had to be BUILT in the first place. Every system in New Eden has been explored now, but at one time the empires had to rely on large construction ships using slow but sustainable warp speeds to make it to new stars and construct the gates. This process could take anywhere from a few years to several decades, depending on the distance between systems.
A great story of the time consuming nature, and dangers, of stargate construction and interstellar flying is the story of the system of Ouperia, which you might know better as Old Man Star.
Read it here.2) Adamance basically said it all. Sanshas Nation is more dangerous than ever thanks to massive leaps in their technology, pointing to them having stolen from the Jove.
The nations "True Slaves" are probably the most terrifying example of the kind of things Sansha did. Cybernetically enhanced cyber-zombies, with all the cold intelligence and calculating of a computer, with no human emotions or morality.
Here's some nightmare fuel!3) I don't believe you can actually own a Jovian ship in EVE (could be wrong, but I don't think any have ever been given away. (SoCT ships like the Gnosis do not count as Jovian, and are more like hybrids of empire technology with a little bit of Jovian influence), and you certainly can't fly one because the required skills don't actually exist outside of the developers console.
Sansha ships can be quite powerful. They have very good shielding and excellent laser weaponry. The specialzed versions of Sansha vessels we see during Incursions are extremely powerful combatants, and it is nearly impossible to face a group of them on your own.