Ask HN: Fair terms for CTO position in funded startup?

As a freelancer I've architected & built the technology behind a client's startup, which is currently in beta, and is valued at $2M, based solely on investment. They've made me an offer to come on as CTO; I'm unsure of how good the terms are. Can other CTOs (perhaps anonymously) post what terms they joined the company with?

1) The position would be a "co-founder" CTO; however, it would not have a board vote. The funders are splitting votes between them 50/50.

2) The base salary is $150k, which is in the bottom 10% of CTO salaries across all company sizes in the region (according to salary.com). The salary rises to $225k once the company is making $500k in profit. However, there's no sales/marketing budget, as they want to grow organically. I'm earning $120/hr contracting for them; I have new clients lining up willing to pay $150/hr.

3) Equity is 7.5%, with 50% vesting immediately, and the remaining 50% vesting over 4 years, with no cliff. Forward vesting (in the event of a sale) is 50%. The company is an LLC, so the equity represents a profit share. It is dilutable, as are all positions (including current funders).

4) Severance "without cause" (cause includes fraud, breach of fiduciary duty, etc) is 6 months pay, plus 100% vesting.

5) Benefits are OK. 3 weeks vacation, 2% 401k match (plus 4% at 50%).

Is this a decent deal or should I hold out for more? Finding a replacement for me given the complexity of the product would be tough. I've started negotiations, but there's no "give" currently, except for the agreement that we'd research to see what is common.