[aglikson]

I guess most of tech articles in general often pay more attention to technology details than to its cost-effectiveness (or even TCO) for certain classes of workloads.

If your workload is a 'traditional' web application, saturating a full VM and not too bursty - don't run it on Lambda.

Regarding vendor lock-in, I don't think Lambda is important for the vendor lock-in question. If you just need 'compute' capacity, it would be easy to move from Lambda to anything else. But if you also use bunch of other AWS services - then moving the Lambda functions is likely to be your least concern, frankly. On the other hand, if you do leverage various AWS services (other than just IaaS) - switching to Lambda (or other managed platform) could be useful to make your entire architecture (more) serverless.