Virtualscratchbuilder summed it up nicely, they each have their pros and cons.
The True North and Battlefront minis are pretty close in size but the Battlefront mini is a little huskier (length and span are the same but the fuselage & wings on the BF mini are thicker). The GFI is slightly smaller but that's to be expected as it's n-scale
but it doesn't seem too out of place in a 1/144 scale environment.
RE: detail on the intake cowling – I would say that it's a tie between the GFI and BF minis.
The pictures were meant to allow for a basic visual comparision but here are some basic characteristics of the minis.
True North – all metal, one piece, engraved lines around the control surfaces, basic decals come with the mini, I added the cannons to the wings, cost is ~$6.
GFI – all metal, 11 pieces consisting of fuselage, 2xwings, 2xhorizontal stab, 2xlanding gear, 2xsets of rockets, 2xbombs, lots of panel lines etc, kit does not include decals but Scale Specialties decals are available through GFI, cost is ~$6.95.
Battlefront – mix of resin and metal, 6 pieces consisting of resin fuselage/wing/tail assy, metal spinner, 2xmetal cannon assemblies, and 2xrockets, lots of panel lines, the box set comes with three minis, basic decals (not the ones on the pictured mini) and small clear flight stands, cost is ~$45 to $50ish per box of three (~$15ish each).
I enjoyed working on all three kits and reserve endorsing any one in particular.
My personal preferences in this scale are generally
a good clean casting that looks like the actual plane, one that "scales-out" about right, metal (more forgiving than resin), subtle engraving (for me, less is more at this scale), fewer parts, parts that fit well, approrpiate ordnance/weapons, pilot/crew figures if open cockpit, decals provided, and not too expensive.
v/r Kevin