From what I recall, they all come in slightly different width and length fittings so you need to find the boots that most closely resemble your horse's natural foot shape. I have used Cavallo Simple boots in the past and was pleased with them but they may not fit your horse's hoof shape. Could be worth an email to the Hoof Boutique with a template of your horse's hooves to see what they recommend.
Is the breaking due to natural wear and tear ie self trimming? If it's just nibbles around the edges it's often just that. Is the horse footsore? Is the hoof cracking, or a chunks coming off? Pictures would be useful. Meanwhile, you will need to measure the feet, have a look at Hoof Bootique website for lots of info and choices.
Best boots are the ones that fit - which varies by horse. You can try second hand ones if you don't want to buy expensive kits.
Back feet seem to more commonly be longer and thinner than fronts (at least for mine) so I wear the slims on the back and normals on the front.
I just cavello - but clumpy but forgiving on sizing.
I have a £40 second hand pair that lasted over a year for occasional hacking routes that were particularly stony
I use scoots, but if you contact the hoof boutique they will advise you of the best style for your horses hoof shape. They send out fit kits etc. they are very helpful