The tangible, good quality ‘printed version’ will be the best option to create a professional look for your business.
Try to make sure copies/emails arrive at the weekend, when recipients will have more time to read the newsletter and partners are more likely to be around to jointly discuss any aspects.
Where possible, follow-up the despatch of the newsletter.
Understandably, the best response will come from existing clients, who have also been known to pass the newsletter onto their friends and relatives.
At the other end of the scale, a door drop to unnamed individuals is likely to generate less response - although it will be cheaper than inserting into envelopes and posting out. If you adopt this approach, go for greater volumes to increase your hit rate. And remember, the more copies you buy, the cheaper the unit price becomes.
Familiarity works with newsletters. You'll enjoy much better name awareness and reader empathy once the recipient has received 3-4 issues. And by targeting them on a regular basis, you're more likely to hit them at the time they're thinking about a new mortgage, remortgage, life cover, secured loans, etc.