don't forget that the forward slash "/" is a special character in elastic search. so try searching service logs by http route and you are completely f&^$ed.
Papertrail/Timber.io - cheapest way to aggregate logs and has simple search functionality.
Scalyr - my personal favorite. Just a little more costly than Papertrail, but can do as much as any full service SaaS - powerful queries, dashboards, and alerts. Takes some practice to learn, but their support is very helpful.
Sumologic - Fully featured log agregator. It works pretty good but their UI is super duper annoying. You have to use their tabbing system on their page, you can't open multiple dashboards/logs in multiple browser tabs. For the money, I personally prefered Scalyr, but this is a reasonable option.
Splunk - a great place to $plunk down your $$$$. I think their cheapest plan was $60k/yr, but I will admit that it was easy to get going and use and also had the most features. It's not a bad bang for your buck as long as you have lots of bucks to spend.