What kind of multiparty computation is this?
There are roughly two common techniques for multi-party computation, garbled circuits and secret sharing. Either may work for your situation, so I've detailed some info and recommendations about each below.

Garbled Circuits
GC is most often applied to the 2 party case. It can be made to be secure against malicious adversaries and can be fairly efficient (a single execution of AES in 1 sec on a massively parallel machine). Against a semi-honest (or honest-but-curious) adversary, a single execution of AES takes about 0.2 seconds (this is on a single thread/process).

Secret Sharing
There are many secret sharing based protocols out there. They typically aim for as many parties as desired (with a cost of extra communication &amp; computation per party). They also can be made to work in the malicious model. Any secret sharing technique can theoretically be used, but the most efficient protocols have used (somewhat) homomorphic encryption.

The SPDZ protocol was recently used to compute an execution of AES in less than half a second with up to 10 parties. The timing result only takes into account the online phase. There is a preprocessing phase which takes more time (haven't been able to find exact numbers), but still appears to be manageable.

Fully Homomorphic Encryption
Fully-homomorphic encryption can easily be used to compute on encrypted data, in the malicious model. But, it comes with its tradeoffs. The communication complexity is much less than any of the other protocols, but (currently) the computation complexities are too large to be practical. For example, homomorphic evaluation of AES was shown to take a few days using the best of the best available FHE systems.