Our clients have had great success with the motorola PTP 600 bridge. Latency is ~1 or 2ms as promised and throughput is excellent. We have a customer doing 60 miles with one of these and ONLY 4' dishes.
You could also look at the Radwin 2000 and the Exalt wireless bridges. The Radwin is less expensive but has a slightly higher latency and the Exalt is great is areas with a high level of RF noise.