Is a comparison table available somewhere?
F300-25L has offline Spectrum Analyzer and throughput upto 400Mbps are the key differences.
The sensitivity and power of the radio is noticeably lower with the F300-25L. The CPU is also weaker, although that’s the smallest problem. In the same location, it reports 6 dBi lower signal level on RX side. On TX side (reading on AP) it is lower by 2-3 dBi. However, it can maintain a higher MCS than the F300-25 version with a difference of about 3 dBi. So it could be a software difference related to a different background noise calculation.
What changes have been made that reduce throughput to 400Mbps?
The standard Force 300-25 has a higher performance processor enabling up to 600 Mbps compared to the Force 300-25L which is limited to ~400 Mbps.