Minecraft – Name an Armor Stand using the Standard Galactic Alphabet

As far as I could tell from experimenting, the enchantments provide random effects, but the level of the effects is based on experience spent. So, an exp-level-5 enchantment is much more likely to be a level II or III version rather than a level I version. A sword with "Sharpness V" does a lot more damage than one with "Sharpness I", for example. It'll be a much higher-level enchantment spell, too.

Some enchantment spells create multiple effects, and I think the total level of all effects is equal to the spell level. So, a Level-I sharpness plus a Level-II Fire Aspect would be something like 7 exp levels (2 for sharpness, plus 5 for fire aspect). I need to figure out the actual exp level to enchantment level curve, but I think each level (I, II, II, IV, V) requires substantially more experience.

You can boost a thrown Ender Pearl using a TNT cannon. Assuming you've got the trajectory exactly right and have a wall at the destination to stop the pearl, this is basically instantaneous other than the fuse time (4 seconds). Also, in one step you can only travel as far as the chunk load distance, which as far as I've read is 160m (10 chunks), or else the pearl will not land until you move closer. So, speed: 40 m/s average, less time to gather resources and place the TNT, and the flight time of the pearl (which will depend on the amount of TNT used and exact trajectory).

If you built a series of redstone-driven TNT magazines wired to operate in sequence and launched pearls perfectly to match them, then you could avoid waiting 4 seconds and move even faster.