There are a lot of options, some maybe not quite compliant if you have an inspector that is particular on details and up to speed on their knowledge of listings, etc.
NEMA contactors/starters will generally be the most expensive, but also will generally have highest number of rated operations for the lifetime of the unit. Definite purpose contactors/starters are likely the least expensive - but technically are only a recognized component and you basically need to be a manufacturer to use them for anything but replacements in a listed assembly - I still see a lot of them being field installed though.
IEC contactors/starters will be considerably less then most NEMA units, usually will be smaller in size and will have less rated number of operations for the lifetime of the unit.
Those rated number of operations seldom mean a lot because field conditions usually cause a failure before the basic number of operations becomes an issue from my experiences.
All of those mentioned are available as open devices (provide your own enclosure), or with a enclosures specifically designed to house the contactor/starter with a variety of enclosure types - NEMA 1, 3, 4, 12, 13, 13x... many also can incorporate disconnecting means and control switches into the enclosure - often known as a combination starter. "pump panel" is basically a combination starter with a fused disconnect, motor contactor and overload, hand/off/auto switch and start pushbutton (for use in the hand mode), and ordinarily is suitable for use as service equipment as well. Pump panels is usually one of the lesser expensive ways to go around these parts - but partly because there is a high volume of them sold here for irrigation applications, this may not be the same for your area.
