A cleared swap faces the clearing house. As a centralised trade depository the clearing house imposes margin requirements, as a kind of insurance for their perceived lower credit risk. Margin is nowadays remunerated at local currency OIS I believe. The collateral is posted in local currency (or USD depending upon product) and remunerated at local OIS. Margin is often calculated based upon net risk.
An OTC swap has a collateral and remuneration stipulated by the terms of the credit support annex (CSA) which is a part of the ISDA Master Agreement drawn up between the two specific counterparts. It can vary significantly to the terms with the clearing house (currencies, remuneration, allowable securities, timing of exchange, etc) although typically there is no margin on OTC swaps, and some may even be unfunded or uncollateralised.
If all the terms are the same as the clearing house then there will be minimal difference except for the clearing house margin. However, the (Basel III) capital requirements/ratios and credit risk concerns for the OTC swap are likely more onerous.