On the tax side, SPXS has an higher taxable income
Synthetic ETFs are more risky due to the use of swaps. Based on previous posts, VOO has better performance and lower taxation.
However, this assumes you are able to retrieve the full refund of the withholding tax through DA-1, which is not always the case: Vaudtax DA-1 reimbursement denied
I think SPXS makes sense if you live in a country without double tax agreements or if you need to take an european ETFs. SPXS will have better performance than full replication ETF based in Ireland like VUSA.