Actually the Tweed is a pretty Killer module...inspired me to buy a Kendrick Tweed amp which is why I am selling the Randall RM20B combo and the remaining modules.
The Tweed and the JTM are similar. The Randall website says the Tweed module is perfect for SRV type tones but I actually likes the JTM better for SRV. The Jtm has a little more British chime and a touch more gain. The Tweed seems to have a little more mid range. Definately different modules but not drastically so. A good American-British contrast within the same gain range and type of tone.