Grammar JLPT Level N3 - Lesson 16

Like として, にして highlights an aspect of something from which another thing happens. The primary difference being that と implies that (B) results from (A), while に implies that (B) happens/exists at the same time as (A). This reflects the case marking particle に's use as a location. The adverbial particle は presents the entire (A) phrase as something that will be compared.
にしては is regularly translated as 'considering (A), (B)', or 'even for (A), (B)', and may be used with both verbs and nouns. Like として, にして is often considered as a stand-alone adverbial particle, despite stemming from several parts.

• 彼(かれ)は毎日(まいにち)漢字(かんじ)の勉強(べんきょう)をしているにしては全然(ぜんぜん)漢字(かんじ)を読(よ)めない。
  For someone that studies kanji every day, he can't read it at all.
• 始(はじ)めたばかりにしては結構(けっこう)じょうずだね。
  Considering you have just started, you are considerably good.
• 田舎(いなか)にしてはコンビニがいっぱいあるね。
  Considering that this is the countryside, there are many convenience stores.
• あの人(ひと)は俳優(はいゆう)にしてはあまりイケメンじゃない。
  Considering he is an actor, he is not very attractive.

Despite the 'considering (A), (B)' translation, にしては is closer in meaning to 'while (A), (B)'. This expresses that (A) and (B) share a simultaneous relation, but also that (B) is not necessarily a result of (A) at all.

• 中卒(ちゅうそつ)にしては頭(あたま)がいいけど、大卒(だいそつ)の同級生(どうきゅうせい)と比(くら)べるとそうでもない。
  Considering that he is a middle school graduate, he is smart, but compared to a college graduate of the same age he is not that smart.
• 新人(しんじん)にしてはよく働(はたら)くけど、他(ほか)と比(くら)べるとあまり働(はたら)いていない。
  For a new worker he works a lot, but compared to others, he doesn't work that much.