The Meteor Mk. I certainly wasn't the Me262's peer in terms of performance. It was very lack luster in that department, just a little faster then the best prop fighters at the time.
The Meteor Mk. III on the other hand would definitely be a better choice in terms of "adding something of value" in terms of performance. As it stands, there's a massive jump in top speed from the K4/P51D/La7/Tempest to the Me262; the Mk. III would fit somewhere in between.
The Mk. III saw extremely little action in the last month of the war in Europe. The war ended with the Meteors having destroyed 46 German aircraft through ground attack. However, the Mk. III does indeed meet HiTech's criteria for adding new planes to Aces High: It was in squadron service and fired its guns in anger. It would definitely be the most rare and exotic additions to the sim.
Finding plausible performance data for the Mk. III is proving rather hard. But I found the following information posted in ww2incolour's forum:
"I was lucky to find the following data in a book "WW2 - Aircraft", by Christopher Chant, (Orbis Publishing Limited, London, 1975)." which stats the following performance data:

Gloster Meteor F. Mk III
Powerplant: 2X Rolls Royce Derwent I, 907 kp of static thrust at sea level
Maximum speed: 793 km/h (492MPH) at 9150 m; 737 km/h (458MPH) at sea level
Armament: 4X20 mm Hispano Mod. III, 195 shells per cannon
Range: 2157 km, with 563 km/h cruising speed at 9.150 m
Service ceiling: 13,100 m (42,979ft)
Velocity of climb: 1213 m/min. (3979ft/min)