The Isabell, like any of the Bates/Wintec models, offers good value for the money. The tree is pretty flat, and the front panels aren't really deep, which means it's a good choice for a moderate wither, but not so good for a mutton wither or a steeple wither. The changeable gullet can be helpful as long as width is the only issue that needs addressing, since it does nothing to correct problems with panel configuration or tree shape. The CAIR panels can work well - but they don't breathe (problematic in hotter climates) and will expand and become rock hard in high altitudes (think Denver). The fitting system consists of shims, so you need to find a fitter who has the shims and other tools needed to drop the panels and adjust the fit.
In short (which I haven't been

), the Isabell is a good investment if it fits your horse.