These are pretty decent for a scope. I have one of those Night Spirits 2 (acquired from ebay for ~500 bucks), so the Apex price is a tad better. Stock they will outperform any single stage Gen1 by a long shot... but the kicker is that at just 449 bucks, the Night Spirit 2 Intensifier Tube can be modified for increased gain which will make it a lot better than stock; night and day difference... (I am sure the PS-14 has a similar tube inside and I bet it can be made even better as well) The optics are fairly decent as well, at F1.2 on the main lens.
But to try answering your question, and considering the Fero is a Gen1 cascade tube IIRC which has very good light gain, I think the size/weight reduction alone is worth it... but I also think you'll like other features like ABC or BSP, like when you look at bright scenes the scope reduces the gain to protect the tube... probably a lot less distortion than the Gen 1 scope...
You can look at the thread for the Apex Bringback Scopes or the Modifiy EPM66G tube gain, you'll find some info on these scopes there.
I think stock light gain on most of those Gen2 Russian scopes is in the 20,000x ballpark with S-25 Photocathodes.
Hope this helps.
G.