Not bad choices. Are you going to modify them or keep them 'box stock'? There are a lot of options for these kits, improvements of various kinds if you wanted. I kind of kept my Aeromax 'box stock' just because it was so simple and yet it has the right look. The Flat-Bed is pretty good (although I always thought it needed a bit of a stretching - just an inch or two), but it's not bad as a beginner set.
If I could suggest the addition of the MFU (for sound & light in the tractor) and the Motorized Support Legs (automatic landing gear) which make it fun to drop & hook your trailer. It also makes for a wonderful show piece when your finished.
Whatever you do, I'm sure it's going to be a great build. Take your time and do it your own way. Make sure it's what you want and always HAVE FUN - It's only a hobby.
- RCT