Ask HN: What's the best way to break up charges for recurring billing?

I recently had a conversation about the best way to do recurring billing. We identified a few pros and cons for a variety of approaches. I am interested on the HN take. (NOTE: This is technology agnostic, and more of a conceptual discussion)

1) Prorated First Month, all recurring clients are billed on the first. + Cash flow at the beginning of the month + Cash flow lines up with bills. + Easy to do maintenance on recurring billing system (only runs once a month) + Reasonably easy for users to understand - small partial month transactions for people who order late in the month.

2) Prorated 1st month with 2nd month prepay + (all of the above) + Even more cash flow early on, as every client is always one month ahead on payments - some clients might not want to prepay for 2 months at once - bill might be different then what the expect to pay, i.e. signup now for $15 costs them $29 (if they order on the 2nd of the month)

3) Everyone is on a 31 day cycle + everyone charged a flat $15 for every charge. - Billing period slowly shifts around, not the same day every month - cash flow spread out throughout the month - harder to do maintenance, as billing must run every day

Other ideas: 4) Only Annual + large amount of cash on hand - might scare away new users

5) Instead of prorating first month, call it a trial period, that starts 'now' and ends whenever your billing cycle begins. - confusing to end users - lost revenue due to trial

What is 'your' take? (your.. the collective HN)