In SFBM, the Warbird and Romulan Battle cruiser have 6 cloaking generators. Per the rules, an undamaged device, if fed 6 units of energy, can cause the ship to disappear in the same turn. For every generator damaged, you still need to allocate 6 units, but it takes more turns to disappear. This effectively renders the cloak useless when damaged, even if it takes just one hit. A captain would be unwise to use those 6 units for multiple turns and get no benefit out of it until several turns down the road. Those 6 units would be better spent in shields or weapons. Especially when fighting the Feds - those photons bouncing around, since they ignore shields after the first one - it is likely a Romulan ship would suffer a cloak hit. When taking a Battlecruiser, it seems a poor trade to mark off one-half of the ship's weapons for a device that will be practically useless after one hit.
We play with a house rule: The Warbird and Battle cruiser still require 6 units of energy to cloak. An undamaged device has a rating of "6", so you can allocate all 6 units and cloak the same turn. If it takes a hit and is lowered to "5", that is the maximum energy that can be fed into it during one turn. It still takes a total of 6 to cloak, so you could allocate 3 this turn and 3 the next. Or 5 and 1. Or 4 and 2, etc. The generator will save the energy and once a total of 6 is saved up, the ship can disappear. Note that, however, if the cloak is damaged, you cannot feed enough into the device to maintain the cloak and will reappear the next turn. But, it could be enough to escape or get out of a tight spot. All other rules pertaining to targeting while cloaked still apply. I believe this new system is an improvement over the original rule. It makes the device still usable after a hit and still poses limitations since a damaged cloak cannot be used continuously.