I've been using Interspire Email Marketer on a daily basis for 7 years, have purchased about 10 copies of it for various clients & corporations, and own 3 copies myself.....and this week I'm busy switching my company over to MailWizz. That's saying something. So here's the deal: IEM works great for what it does - if you want a solid, reliable, configurable email tool, it's wonderful. The price is a little painful at $450+ for each single-user license, but otherwise it's a good tool. The PROBLEM started when we outgrew what IEM was able to send in a day. It's single-threaded, so we purchased the Maborak multi-thread add-on. That took a LOT of time to install (it requires ioncube, and since our command-line PHP is diff than our cgi PHP, it meant updating paths inside the add-ons files to get it working). Yuck. Got it solved, though. However, our send rate didn't seem to increase, and IEM offers ZERO tracking for deliverability, which is an issue that we ran into when we cranked up MailWizz the first time. So, now that I've done 3 or 4 big campaigns on MailWizz, I'm pretty happy with the platform. PCNTL is installed by Default on Dreamhost Dedicated LAMP servers, so on campaign #3 I cranked it up to 50 threads processing 500 messages each, and ran through the entire 100k email list in about 45 minutes on our server. Unfortunately, our SMTP server couldn't handle the load - which we resolved dropping the parallel threads until our deliverability monitor showed it 100% again. Big Advantages of MailWizz over IEM: 1. Price. In fact, MailWizz should cost more, I think. I'd charge $100 for it, but I'm not complaining about the lower price. I'll buy another copy today so I feel less guilty about the performance vs. price point. 2. Parallel-Processing. It works like a champ. Actual throughput seems a little strange, though. 50 threads should send around 2x faster than 25 threads. Seems like 50 threads ACTUALLY sends like 4x faster. Maybe that's because our SMTP host was dropping messages, though. 3. System Load. Very nice loading. We have a big, fast server, but with multi-threading installed, IEM was a dog. Took 30 seconds to even reload the campaigns page. MailWizz is fast & responsive, even running it full-bore. Good memory consumption, too: 50 threads @ 500 messages each created a bunch of processes at around 275mb each, even though I gave it as much RAM to play with as it needed. 4. Lots of Modern Bells & Whistles. Built-in inlining for HTML messages, minifying, a modern WYSIWYG editor, etc. The WYSIWYG that IEM uses is actually an updated version of one they've been using since at least 2005. MailWizz feels contemporary. 5. Better reporting. More reports, more details, and more granular information that you need to know if you're sending. IEM does reasonably well with high-level info about your campaigns, opens, clicks, unsubs, etc - but MailWizz takes reporting a lot further, and gives you a much better overall picture of performance, especially at the system level. Some wish-list items: 1. Real-time monitor. It'd be nice to be able to track processor, RAM, network, and MySQL utilization during the send. Two ways to do this: first, as a version of the "top" command (which I use on our server while it's running), or second, as a mini web-app that you could launch in a separate process that would automatically reload every 15, 30, or 60 seconds. Obviously you don't want/need to rely on this all the time, but especially when you're first setting the machine up, it'd be neat. 2. I wish it was easier to switch from the front-end to back-end modes (maybe a toggle in the login ID, and then automatically create a front-end user for the admin: after all, a LOT of users will be single-user owner/senders). 3. Bounces go to email "blacklist". Not sure if they HAVE to, but I use my blacklist for critical stuff, and adding bounces to it screws that up. It'd be better simply to mark them as "bounce" or "dead", and then not send to them. That's how IEM does it, and it makes them a bit easier to manage. 4. Senderscore/MX-Toolbox integration. Obviously this is a wish-list item, but it would be neat to be able to see IP/domain reputation & feedback information in the app itself. 5. Ability to disable/hide features. It don't use autoresponders, don't use articles. Would be neat to be able to remove those from the menu. Maybe the app would be faster if they were turned off? Something like that. 6. Built-in notes/ideas on optimization. Maybe the community in this forum could help with that. A lot of folks have the ability to tweak their settings for PHP, mysql, etc. Would be nice to have a popup that gave you speed pointers for every aspect of the system.