Yesterday, I played my first games with my Saim-Hann army at the first Epic meeting in Britanny (the west 'peak' of the France).
The first two were 1000pts games "Minigueddon". Very small game, but it is great to introduice the game to new player.
Well I was playing Biel-Tan, because Saim-Hann restrictions unable me to play formations I wanted to play (Scorpion & Storm Serpent, 4 formations and only one BTS).
So I played a Guardians Host, a Shining Spears Host (2 Exarchs), a Scorpion and a Storm Serpent.
From these games, I learn having an undestructible portal is not an option, but an obligation !

So now, I will always put a Wraithgate in my armies !
And the meeting endded by a 3000pts versus a Tyranid player. Well my antigrav army was the nemesis of Tyranids. I really enjoy the speed of that army.
Saim-Hann relying on jetbikes, an army should always containt two Storm Serpents and a Wraithgate IMO.
And Swooping Hawks are valuable, being the only formation (with Spectral Spiders) able to enter freely into cover. Every other Saim-Hann formation contains mounted infantery, light or armoured vehicle.
I also noticed that if no aircraft is taken, the army will get relativly few activations due to "2 Troupes per Host" (aircrafts do not take a 'troupe slot', and if titans are taken, well high cost formation equals fewer formations).
So I think a 3000pts Saim-Hann army will not often get more that 9 activations (avatar not counted), which is not a lot for an eldar army.
This gives a real identity to the army.