But surely that's the point? These consoles aren't really balanced against anything but each other so it's a case of picking your poison and running with it. For me these are very good consoles as they'll buff Captain skills as well as BO skills (I only run Engineers in a Cruiser) whereas a Sci might choose the T3 Excelsior and the Oberth console for the extra power the efficiency bonus grants.
I'm not actually sure they can even really be compared, every other console grants a clickable skill or ability whereas this grants a passive buff which is always there so while the buff may look weak it's always going to be available rather than on a 3 minute cooldown as the other consoles seem to be.

Honestly, and I've posted this on the Tribble section, I think the combat bonus could work out to be a fair trade for taking up a once free consoles slot. What cheeses me off is that they take away powers I already paid for, expect me to buy them again from the T3 and waste a second console slot for a lower bonus.

If they simply gave the T5 console back the transwarp powers they took out (because I've already paid for those) and buffed the performance modifier by another 1 - 2% I would be perfectly happy. In that state the T5 Excelsior trades a console slot for its once innate abilities plus a moderately useful combat ability, and it still retains 8 free console slots just like the other Retrofits that had their special power turned into a console but gained a slot in the process.

Just from the T5's point of view though as long as the console remains the ship has been hurt. Having to sacrifice a console to get what you already had is simply a bad situation to be in.

This would be true even if the console was undenyably worth using. But it isn't.

I've just had a look on Tribble to see exactly what this console does for power levels. I tried both the T3 and the T5 consoles on the same ship (T5 Excelsior, 9 in all Efficiency skills except Weapons, 9 in Shields and Engine performance, 5 in Aux and Weapons performance with one efficient BOff and no space traits on the Captain). the ship was equipped with a full Borg set and a single Mk XI uncommon Injector Assembly.
Power levels were set to 100/25/50/25 and read as follows before consoles;

116/61/84/58

The T3 Console added a couple of points of power in total and raised them to;

116/62/85/59

The T5 console was then added. This gave the following power levels;

118/64/86/61

An increase of 7 points in total, plus the transwarps plus the increases to Engineering skills. If I could use this console on my Galaxy R I'd be more than happy to ditch the Halon console for which I gain a huge 850HP over 15 seconds and one point of resistance for the duration.
If it's just about losing the console slot then I can't agree there either. Every ship is going to be losing a console slot to use the special ability, although the Excelsior will be losing a console and ships like the Galaxy R will gain a slot to accommodate the console the Excelsior was always the outlier, even the Defiant R was short a console to house the cloak. I really can't see why these consoles are considered weak.

Someone posted in the Tibble patch notes what may be the best solution to the T5's problem. Make the console just a proficiency boosting console and keep the transwarp powers innate since no other ship can use them anyway. That way no one loses anything they paid for, but players can still choose if they want to use the T5's console or not if they think a different console is going to be more useful to their needs.

I thought Performance adds Directly, Effeciency adds on a scale and MAintenance does nothing but affect certain abilities directly?

As did I. I must confess I've never actually checked, it adds power and buffs Eng skills so I add as many points as I can although I usually fall short. I'm sure there are many others who know more than me that can shed more light on the way it works.

Your +7 is only due to a remainder carried forwards from the efficiency console.
Remove the T3 console and compare your base numbers to numbers with the T5 one. It wont be close to +7.

Your skills are rather atypical. For a proper measurement I run at 100/25/25/50 and I have 9/9 all efficiency except weapons, 9/9 warp core training, 9/9 all performances, 1 efficient BO and Efficient Captain trait. I figure more people are like me than you.

Adding either console for me gets me 5 points spread across the 4 power levels. No way is that worth a console.

I'll try and help a bit.

Efficiency and performance @ 9/9 both at +52 to the "skill"

As you know the ammount of actual power this adds depends of a scale.
For Efficiency the ammount added is between 0 and 15 depending on what your power setting is set to. +15 @ 25 and +0 at 75.
For performance the amount added is linear. Take your skill total (52 at 9/9), divide by 5.2 and that is the bonus you get to the power setting. So the performance console at +7.6 is only adding 1.46 power to each of your power levels. This will usually be 1 but the game records remainders so it is possible for it to be 2 if you have efficiency skilled.

OK i still don't have the console, is the copy from holodeck to tribble broken for this? Or perhaps the conversion is not working. I tried to purchase it but it says I already own it, so how do i get the console?