Demon/Dark build any good?

Hi all, is this any good for a tankmage demon mm, i have'nt played mm's much mainly blue side i play but this demon set looks like really fun to play, my demon is currently level 12 and fun so far, here's the build i plan on using, any help will be welcome, Thanks in advance johnny.

Villain Plan by Mids' Villain Designer 1.703
http://www.cohplanner.com/
Click this DataLink to open the build!
Level 50 Magic Mastermind
Primary Power Set: Demon Summoning
Secondary Power Set: Dark Miasma
Power Pool: Speed
Power Pool: Fitness
Power Pool: Presence
Ancillary Pool: Mace Mastery
Villain Profile:
Level 1: Summon Demonlings -- BldM'dt-Acc/Dmg(A), BldM'dt-Dmg/EndRdx(3), BldM'dt-Acc/EndRdx(3), BldM'dt-Acc/Dmg/EndRdx(5), BldM'dt-Acc(7), BldM'dt-Dmg(7)
Level 1: Twilight Grasp -- Theft-+End%(A), Theft-Acc/EndRdx/Rchg(9), Theft-Acc/EndRdx/Heal(9), Theft-Acc/Heal(17), Theft-Heal/Rchg(19)
Level 2: Lash -- KntkC'bat-Acc/Dmg(A), KntkC'bat-Dmg/EndRdx(19), KntkC'bat-Dmg/Rchg(21), KntkC'bat-Dmg/EndRdx/Rchg(21), Mako-Dam%(50)
Level 4: Tar Patch -- RechRdx-I(A), RechRdx-I(5)
Level 6: Enchant Demon -- EndRdx-I(A)
Level 8: Crack Whip -- Ragnrk-Dmg(A), Ragnrk-Dmg/Rchg(23), Ragnrk-Acc/Dmg/Rchg(23), Ragnrk-Acc/Rchg(36), Ragnrk-Dmg/EndRdx(37)
Level 10: Hasten -- RechRdx-I(A), RechRdx-I(11), RechRdx-I(11)
Level 12: Summon Demons -- BldM'dt-Acc/Dmg(A), BldM'dt-Dmg/EndRdx(13), BldM'dt-Acc/EndRdx(13), BldM'dt-Acc/Dmg/EndRdx(15), BldM'dt-Acc(15), EdctM'r-PetDef(17)
Level 14: Super Speed -- Empty(A)
Level 16: Hurdle -- Jump-I(A)
Level 18: Health -- Heal-I(A), Numna-Regen/Rcvry+(46), Mrcl-Rcvry+(46), RgnTis-Regen+(50)
Level 20: Stamina -- P'Shift-End%(A), P'Shift-EndMod/Acc(43), P'Shift-EndMod(45), P'Shift-EndMod/Rchg(46)
Level 22: Fearsome Stare -- Abys-Acc/Fear/Rchg(A), Abys-Fear/Rng(37), Abys-Acc/EndRdx(37), Abys-Acc/Rchg(40), Abys-Dam%(40)
Level 24: Hell on Earth -- ExRmnt-Acc/Rchg(A), ExRmnt-Acc/Dmg(25), ExRmnt-Dmg/EndRdx(25), ExRmnt-Acc/Dmg/Rchg(31), ExRmnt-EndRdx/Dmg/Rchg(31), ExRmnt-+Res(Pets)(33)
Level 26: Summon Demon Prince -- BldM'dt-Acc/Dmg(A), BldM'dt-Dmg/EndRdx(27), BldM'dt-Acc/EndRdx(27), BldM'dt-Acc(29), BldM'dt-Acc/Dmg/EndRdx(29), SvgnRt-PetResDam(31)
Level 28: Shadow Fall -- LkGmblr-Rchg+(A), LkGmblr-Def(33), S'fstPrt-ResDam/Def+(33), HO:Enzym(34)
Level 30: Darkest Night -- SipInsght-ToHitDeb(A), SipInsght-%ToHit(34), SipInsght-Acc/ToHitDeb(34), SipInsght-Acc/EndRdx/Rchg(36), SipInsght-ToHitDeb/EndRdx/Rchg(36)
Level 32: Abyssal Empowerment -- EndRdx-I(A)
Level 35: Howling Twilight -- EndRdx-I(A)
Level 38: Dark Servant -- SipInsght-ToHitDeb(A), SipInsght-Acc/ToHitDeb(39), SipInsght-Acc/Rchg(39), SipInsght-ToHitDeb/EndRdx/Rchg(39), SipInsght-%ToHit(40)
Level 41: Provoke -- Zinger-Taunt(A), Zinger-Taunt/Rchg(42), Zinger-Taunt/Rchg/Rng(42), Zinger-Acc/Rchg(42), Zinger-Taunt/Rng(43), Zinger-Dam%(43)
Level 44: Scorpion Shield -- LkGmblr-Rchg+(A), LkGmblr-Def(45), HO:Enzym(45)
Level 47: Web Envelope -- Enf'dOp-Acc/Immob(A), Enf'dOp-Acc/Immob/Rchg(48), Enf'dOp-Acc/Rchg(48), Enf'dOp-Immob/Rng(48)
Level 49: Power Boost -- RechRdx-I(A), RechRdx-I(50)
------------
Level 1: Brawl -- Empty(A)
Level 1: Sprint -- Empty(A)
Level 2: Rest -- Empty(A)
Level 1: Supremacy
Level 6: Ninja Run

Would you mind posting the data chunk? The link is broken.

Off-hand, you're focusing way too much on your person and not enough on buffs. Stamina can be delayed long after level 20 - Darkest Night ought to be taken ASAP. If you're really aching for an early-maturing build, move your travel power. Flight packs only cost 10,000 and they work ably, as does the Raptor Pack and Zero-G Pack.