At that price range the DNT Thermnight TNC225R multi spectral scope is far and away the best bang for your buck
The only stand alone thermal scopes in your price range are the IRay TP25SE which sells for £900 and the HIK Thunder TE19 which sells for £1k
In terms of thermal specification, all 3 scopes use the same 12 micron 256x192 sensor, the Thermnight and the Iray have a 25mm lens, but the HIK only has a 19mm lens
The Thermnight sells for £950 and, as well as a thermal sight it is also a colour day and Night vision scope with onboard IR illuminator, laser rangefinder and ballistic calculator.
Honestly, for the money nothing comes close to what this scope can do
Cheers
Bruce