This question is asked over and over and most, including myself, will tell you to do as much research as possible and then decide what suits you best. Some will just point out that their chosen brand is the best. Today, I am in the mood for rambling so here is my lengthy dissertation.
In the Cobra world, "best" generally is synonymous with "most accurate" or cars that are engineered and designed to most closely replicate the original in areas like dimensional accuracy, components, drivetrain, overall quality and the elusive "correct" look and stance. Stance is the height and rake of the car and the relative position of the wheels
in the fenderwells (as opposed, for example, to cars that sit a$$-high with tires bulging beyond the fender lips).
Aluminum-bodied Shelbys and Kirkhams top the pecking order and you pay accordingly, with the Shelbys packing the additional cachet (and price) that comes with being blessed and sold by The Man Himself.
Premium fiberglass bodied cars are very accurate in dimensions, components and appearance, are generally engineered for FE powerplants and ALWAYS have independent rear suspensions (IRS) as on the original cars. People argue the merits of IRS vs. live axles - and both have their strengths - but the reality is that among Cobra replicas,
the premium offerings ALL HAVE IRS, period!
The larger, respected, currently operating manufacturers in this group are (mainly) ERA, Superformance and Unique Motorcars, and of course the Shelby 'glass bodied cars. There are other, less prolific manufacturers in this class, like Premier Motorsports that also make a well engineered, accurate looking car.
An important sub-category here are the premium, respected brands that are no longer in production but still show up for sale in the pre-owned market. Contemporary, Butler and HiTech are three very highly regarded marques.
There are many other manufacturers with correct and not-so correct appearing bodies that offer live axle chassis, some with optional IRS that allow the builder start at a lower price point and build the car the way he likes or can afford to do. Some of these brands also allow the builder with relevant skills, time and resources to build a car that can look and perform every bit as well as the premium cars with varying degrees of effort and attention to detail. Some of these bulids also allow the use of donor cars for drivetrains and suspension components.
This category is very broad and includes a wide range of options, features, and levels of quality and engineering to suit an equally wide range of tastes, special requirements and budgets. In no particular order some names are: Factory Five Racing (FFR), Midstates, D&D (Canadian), B&B, Emerson, Lone Star, Classic Roadsters, Everett Morrison and many others.
Special mention is required for FFR (Factory Five). Responsible for much discussing (and cussing) among Cobra enthusiasts, FFR is the most prolific of all replicas. Starting out as a low budget 5.0 Mustang donor kit, they have evolved to offer full non-donor packages and optional IRS. Famous for their distinctive, quirky high "perky butt" look, they are not generally considered a premium brand but they are light and fast, have a huge, loyal owners group and have sold more cars than many others combined. Many FFR builds are a testament to their owners' skill and attention to detail and show beautifully in any group.
Another sub-group is the Cobra-esque hot rod type of car that is designed to look somewhat like a Cobra, but are stretched and bulged in various ways and for various reasons from increased legroom, fitment on donor chassis' and pure racing applications. These cars forsake the "correct" Cobra look with varying and questionable degrees of success based on their owners' priorities and subjective opinions.
A new and popular player in this class is Backdraft, a South African product employing a BMW IRS, available (like Superformance) only as a fully finished roller sans engine and transmission. The body is elongated for more cockpit room and the fenders are bulged and flared in a stylized caricature of the more athletic original shape. West Coast Cobra is a live axled, spaceframe design that also follows this approach. Lone Star and Classic Roadsters have longer wheelbases for more legroom. JBL is in a class by itself and is a high end, longer, lower, wider interpretation that employs an advanced, race-engineered chassis and suspension for awesome track performance.
This is just a small summary of what's out there and in some ways based on subjective opinion. Like you have and will be told, the "best" Cobra replica is the one that makes you happy aesthetically, performance and budget-wise and the only way to be sure is to expose yourself to as many choices as possible. Take your time and do plenty of research. Study the originals and the different replicas and read the threads on this forum. Join local Cobra groups and get to know the different brands so that your final decision will be an educated one.
Good luck.
