Contact Person data upload
We are implementing CRM 7.0 for our client and they have contact person data split in ECC and another legacy system. So we are planning to do a download of contact person data from ECC to CRM via middle ware and then upload contact person data from an (excel spreadsheet, extracted from other legacy system) into CRM. While uploading, there will be create and update scenarios as the legacy system also have few records from ECC system.
Please suggest the options which can be used to upload contact person data from a spreadsheet. Is LSMW the best option for this or is there any other option available to achieve this ?