I have the Mustang and the Spitfire.
I agree with all of the above, you have nicely summed up the pros and cons.
Although I have never had any issue with the retracts apart from having to increase forward rake for grass strips.
They look nice, are a pleasure to fly stock with almost no mods, are inexpensive and just the right size.
One thing I'd like to add to your list:
I bought the spitfire because the scale proportions are so good! So many model Spits have the tail enlarged, or the fuse too thick, or a flat underside. The Dynam is the right shape and size.
They have even got the wing fillets right, all the way down to the slight scallop under the trailing edge of the wing/fuse, giving a gull wing (once I increase the dihedral). Even some static model kits are missing this.
The Dynam spit is a Mk. IX. It has the right tail shape, right number of exhausts, etc. They did their research which is fantastic. Well done.
Perfect candidate for adding some scale details. I can easily fix the blue paint and change the pilot