Newedge will certainly not be viable with a 100K or 250K account. For FX i would look into: LCG (all the ususal multibank platforms - using JPM as pb) Fixi (same, using UBS) LMax (exchange-style order execution, they got the top 10 FX banks and more in their system) And there is really nothing wrong with IB either, except you will be able to get more competitive commissions with the above firms.
Pippi436 has right. IB's can give more competitive commissions..., we can do this as well with Lmax. (Let me allow to mention our service (www.fairfxtrading.com ; we are in partnership with LMAX). Who want to discover the real transparent trading environment, here is a hint: it is recommended and useful to open a real trading account with a lower deposit from $€Ł 1.000 (by Lmax from $€Ł 10.000) instead of a demo one, because it will be an overview of the real trading environment. Looking to open your trading account by Lmax, we will be happy to help you out with that. Feel free to contact us. Unfortunately Lmax does not accept clients from the USA...