I have about 70+ runs on my Wren 54 and have had no problems. I have the manual start and the system has worked just fine. They do offer an auto start version. The manual start saves about 10oz which is why I chose it for my plane. The folks at Wren are great. There are some delays getting a motor right now so I'm not sure what the wait will be.....but it will be worth the wait! I set my timer for 8 minutes and I carry 42oz plus a UAT (4oz) and always land with the uat full plus some in the last tank. Hope that helps.
Cheers, Mike