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These two models belong to two slightly different styles of 'ukulele. The selection between them should be a reflection of your own playing style and musical goals.
The ATP-CTG is a loud, versatile model with decent punch, good sustain, and a wide sound (edit: some may call it boomy). It responds well to most styles of play and is amenable to many different types of strings and tunings. The only issues of note are sporadic flaws in the appointments and a lack of brilliance above the 7th fret. Fair warning: it's very orange and quite loud; you'll stand out if you take it to the average uke group.
The SMHT is punchy and sweet, with a strong midrange and a slight dip in low-end response. While slightly less versatile than the ATP-CTG, it is often superior for rhythm parts (especially fast strumming) and generally preserves more brilliance in the upper register. It also draws less attention to itself with its more muted visual design and appointments.
FWIW, I think a KA-ATP-CTG strung with Aquila Reds (re-entrant or linear) is one of the best-sounding sub-$700 ukes on the market, but it's a bold instrument. Whichever model you choose, expect the instrument to require setup to play at its best. If you aren't capable of doing the setup work yourself,, know that some online retailers (The Ukulele Site, Mim's Ukes, etc.) include this service in the sale price.