SIP/IAX2 Provider in USA

I am moving to the USA from UK in a months time, currently my Asterisk box is connected to the world via Voiptalk’s SIP trunk/IAX2 service - can someone recommend a similar provided in the US. From what I have seen so far it looks like I have to pay for outbound calls, in addition to inbound. Appreciate any recommendations you may have.

What issues would i have (network latency) if i stuck with voiptalk being based in the UK?

Thanks for reading.