The verdict
If you have a stable session that explains your product well and prospects miss it, I'd pick eWebinar. The recording does the selling at any hour and in any time zone.
If your campaigns bring traffic but sales say the leads are thin, pick Outgrow. A readiness quiz or an ROI calculator gives visitors something useful and gives sales answers on budget, size and urgency.
For a small team with limited time, I'd start with Outgrow if you have no good session to record, and eWebinar if you already run one on repeat. They can also work as a pair, with the calculator on the page and the webinar as the next step.