、。
From what I've seen, it's quite a good product.
Literal
I [attributive-の] saw [extent-限りでは], quite good product is-[copula-だ].
~限りでは ('as far as X, to the extent of X') is a hedging expression limiting the scope of the speaker's claim. Here it attaches to 私の見た ('what I saw') to mean 'as far as I've seen.' Notice the が→の substitution: の私の見た instead of 私が見た, because the whole clause is modifying 限り as a noun-modifier. なかなか ('quite, fairly, considerably') is a common intensifier for positive evaluations.