Fillers or Fat Transfer Pros and Cons

Without an exam or even photos I cannot give you an accurate answer. That being said among the fillers available I personally prefer fat transfer. However, the key to success is going to a plastic surgeon with extensive experience as the results are technique and experienced bases.

However please note that you age by three factors - sagging (through gravity and time), loss of volume (counteracted by fillers), and skin texture (determined by environmental and genetic factors). Your fillers should enhance your effect of the lifting if placed appropriately by addressing one of the causes of aging..Most often one of these factors are more out of balance than another and therefore your procedures should customize for what is most needed. Often fillers alone can "stall" the inevitable as they only correct one aspect of aging.
Facelift and Skin resurfacing procedures (laser, Ulthera or Thermage ) and fillers are synergistic so as long as you wait until the Sculptra injection site is soft you should do fine. Not a problem and there is no problem with the timing for a facelift. Sculptra, Radiesse, Jeuvederm, Restylane, your own fat (fat transfer) and other fillers address volume issues, resurfacing procedures corrects surface flaws associated with aging and face lifting addresses the sagging loose skin. Resurfacing procedures address skin texture, color variation (e.g. sun spots)- so all three are synergistic and complementary. It is very common in my practice to do all three approaches to rejuvenation at the same time

It is important when answering your question to be evaluated in person. There is a three dimensionality that must be evaluated as well as the condition of the skin and dermis, the roundness of the face, and adjacent areas that may have dropped. If there are focal areas such as smile folds or small indents, then the fillers such as Restylane, Perlane, Juvederm, Radiesse can be used. When more volume is needed, or deeper placement, then Radiesse, Fat Injections and Sculptra can be done. Fat injections may involve a series of treatments and not all of the fat lives; it's not that the fat is being rejected, it's just that the some of the cells die before they develop enough circulation in the new neighborhood to live.   It is a thicker product then some ready-to-use  fillers. The fillers don't have a rejection possibility, they continue to dissolve after the first day they're placed but their longevity is different in different situations.

The rejection rate of fillers is not a common problem. The techniques for injection and the cost may be greater concerns. The advantage is that Hyaluronic based fillers have the advantage of adjustability and actual reversibility with off label use of hyaluronidase. This is an over simplificaiton and after a thourough evaluation and consultation, a better recommendation could be offered. Following the use of fillers and if you appreciate the appearance achieved, you could consider the use of fat grafting which may involve greater potential risk, cost, and recovery.