Hi Charling,
yes, the disk was my fault. I always worked with Windows-based DAW (my sound-engineer worked with Cubase, Nuendo, Wavelab, and so on), but I decided to go with my Mac, and I bought a new external hard-disk and started to use it as I did for PC, but of course it was FAT32. The tricky thing is that everything worked well, the problem of changing files lenght and position just happened randomly

Now I have 3 hdd formatted with Mac OS (Journaled).
I think it's a great suite Studio Logic.
It gives high-quality programs that can go from recording to mastering with extremely good results (yes, of course something can be little tricky and it's necessary to do strange tricks to obtain the best results, like using functions from several programs of the suite).
I completely agree with you, Platinum plugins are very good, then SpaceDesigner is like hi-quality IR rev (and it's great, as many IR rev are really expensive... ok, Wave IR1 is better, but it's around 800eu and SpaceDesigner does its job very good), Pedalboard has some nice things.
Of course, as you perfectly said, it's just a good start.
If someone need better plugin (for example I use several external plugin and hardware that I like) for his work you have to buy it specifically, but however there is really good material.
About fades problem: it happens that the files created for fades become corrupted and you ear other tracks instead of the crossfades (I mean, other audio that comes into the cross-fades, and it's pretty clear if you put the track in solo mode).
It happened three or four times to me, and all the fades become a real mess.
I had to remove manually all the fades and re-create them (and if you have a project with 50 tracks composed by many takes it takes a lot of time

).
However I am also impressed by the efficiency of the program also. I don't have a really powerful MacBook, just an Intel Corduo 2 2ghz, I put 4gbs ram, and I can work with more than 50 tracks with many plugins working streaming on each tracks.
I just finished to record a suite of contemporary music in which I played several tracks of viola da gamba and doublebass. I had 45 tracks with 4/6 plugins each track, no one freezed.
I just play the project and I don't have any problems.
With PC was almost impossible to do that.
I'm an happy user. Sometimes yes, little buggy, but till now I am happy.