I had the Javelin and was very impressed with the speed and accuracy. Unfortunately the plastic piece that holds the probe broke after about a year, so I bought the Thermapen when it was on sale for about $70. The speed is not really that much different between the two.
Interestingly enough I sent an email to Lavatools and a picture of the broken unit. I did not hear back from them for awhile but eventually they sent me a replacement, which I gifted to my son-in-law and he loves it. Also bought my brother in law one for Christmas and he is delighted with how well it works.