Been a while since I posted but seeing as I play frequently as the Yor (I am playing one game with them right now) I can contribute to this thread.
The major differences you will notice playing as them are that they have a tech tree that is completely different in several branches they start with cybernetic history for instance.
they also have (I just loaded the game to check) inherent race ability loyalty 100 yes 100 (basically you cannot get their worlds to flip)So the colonization rush is much easier as they (or you) don't have to worry about worlds flipping
and an inherent ability + 10 Miniaturization (they can fit more stuff on their ships) makes them a little more dangerous.
The limit of 3 speed for everyone that is not you basically makes invasions against you much easier to handle.
they have an two other bonuses one to soldering and another to social production.
This is a large set of bonuses that are further augmented by the fact that the Yor have access to better research buildings very early in their tech tree.
They do however have one very serious weakness - their economy.
When you start playing as the Yor your economy will be the limiting factor because The Yor don't have a econmy building that is not limited to one per planet yep they are limited to the efficiency center which gives a 25% boost and thats it so if you have 20 planets is quite possible to send your econ to hell in a handbasin very fast indeed. I learned that the hard way. You ether have to buy beg or borrow an econ tech from another race or perform some jiggerly pokerry to make it work.
One advantage they have though is that manufacturing building are much cheaper to maintain.
Strengths: Dependant slightly on how you customerise them but:
A large economy penalty
Now compare this to the Terrans
who have the following inherent abilities
Speed +1 diplomacy + 30 +1 trade and +6 logistics and whatever else you set them up with.
The Terrans have the ability to make bigger fleets but the Yor can make better individual ships
The Terrans have a much better economy and access to econ techs fairly quickly as I recall.
Their + 30 diplomatic bonus + super ability gives them the abilty to barter like crazy for techs (although ther research is nowhere near as good as the Yor with that ability it does not need to be, as they can manipulate other far more easier, and have access to tech that enhances this still further.
Ive played both the Terrans and the Yor and the Yor win for me the Terrans have an easier start but the Yor on the rampage are virtually unstoppable
I play On Tough and my opponents on Intelligent don't know how much difference that makes.