I use Thomas Fawcett, used to use Crisp, but switched to TF when I was forced to start buying from North Country when my former LHBS got stupid. Both are fantastic and IMO hard to discern a difference between the two. That said, I have a new LHBS that gets Crisp, so I may be switching back.
I've used a few bags of Muntons and like Strong, I found the extract to be much less, a much longer cold conditioning required for clarity, and I thought it tasted kinda dusty/grainy.
I have also used Bairds and thought it was good but IIRC it was significantly more expensive than Crisp or TF, and I didn't think it was worth the xtra $$.
You can also get some other TF varieties which I would encourage you to try - Optic (what Fuller's uses), Pearl and Halcyon. I personally really like Halcyon quite a bit.