I've played a Saim Hann themed eldar army since I started my eldar. They caught my eye with their red and racing stripes and are probably the best looking army on a table. And as they are my only army of a size large enough to go to tournaments I field them exclusively for a couple years now. That being said I will throw in my concerns with your list from a competitive point of view. When I create a list I still keep the theme to heart, but there are some things I have come to terms with.
Looking at your list, I feel you lack anti-tank. The council unit is rather small but that helps keep points down. I use a jetseer council with 6 locks and farseer. I almost never upgrade spears and when I do its just 1 or 2. They almost always end up in combat, either protecting my army or aggressively going at the enemy. And one attack doesn't cut it. These guys will win you games, and cost you games I realize. Some games the enemy cannot stop them, others they field a rune priest and laugh all game. Other times the dice just don't like you. My experiences are so mixed with this council unit but over all I like them. I run identical troops, but be warned, relying on GJB's to win you games SUCKS. Their low model count and leadership has lost me easy games. I use vypers as well. I run a single 3 man unit with scatters and shuricannon. 21 str 6 shots is pretty hefty. I might try 2 man squads, for some reason it never occured to me to run them smaller. But they are oh so fragile. Your multiple squads are easy kill points that really hurt your firepower if you lose them too. As for your heavy support. I usually go 2 prisms, since it only takes two to make a str 10 blast. How ever I feel you upgraded too much on them. Their long range is their defense and holo-fields and SS are unneccessary. Also with how quick Saim hann is. The night spinner plays with that strength limiting the enemies mobility and forcing pinning checks.
To field eldar in a competitive environment I feel you need fire dragons. No way around it. And if you are worried about breaking fluff, they are still mounted in a wave serpent. Saim hann utilizes the speed and firepower of its wild host but it still uses foot infantry. Can't fly inside after all! And i'm not sure if you have played necrons yet, but relying on str 6 spam is no longer the way out. You can link prisms, but i'm sure you experienced cover saves before. I hit! I pen! Necron player saves... Your warlocks could throw spears, but if they are in range to do that, either the CCB is flying over your army or you are about to be charged by wraiths or scarabs. Also see solar pulse. Fire dragons like em or not. Another thing I've noticed is I am extremely vulnerable to outflankers. Especially the kind that appear from any edge like wolf scouts or ymgarls. When I play, my army is kind of like water. They push on it and it gives way while hitting the exposed areas they've left behind. But they start coming out of everywhere, I got no where to run. And eldar can't take too many hits before running out of steam. Heh, played a tyranid where he went heavy reserve list and made me go first. It appears GJB are fast enough and to cover both table side edges by turn two. Sucks for them outflanking stealers.
Lastly, all the above posts about shining spears. I bought mine to fully realize the Saim hann theme. But competitively they dont cut it. By the time you tool them up they are 250 points and die to rhino bolter shots. Yes they can do damage. But when I go to tournments, the stuff they can charge that will earn their points back will usually beat them instead. Or its a minimum sized squad that will probably bait them into their death. You could put an autarch with them, but really its just the autarch doing damage. Might as well give him to a GJB squad so they can use his leadership and break him off when the time comes. Ironically my favorite thing about the spears is their BS 4 catapults and the BS 5 cannon. Unless you are an eldar guru who can make magic happen, I'd leave them at home.
All that said, I love the eldar and they perform really well. Just some times it feels like I bring knives to a gun fight. But that is probably just the codex creep.