I received an i clear 30 with my MVP 2 last week. I was skeptical because I have used CE4/CE5 clearos and hated them. I did not like the wicks, or the burnt hits (I tend to use 70/30 or 80/20 VG/PG e-liquids). I went to bottom coil Kangertech Protank, T3S, and Evod and loved all three. Since the Protanks have started leaknig I'm not sure I would recommend the Protank v1. Maybe the v2 and v3 are better.... But I digress.
I was blown away by the i clear 30 on my MVP 2. This thing hits like a freight train and I never get a burnt hit. As mentioned above, what voltage/wattage are you using and what it the resistance of the coils? My i clear measures at 2.1 ohms and I set my power to 7 watts, and like I said, hits like a freight train.
If you're looking for Pyrex, then the Kangertech mini Protank would be a good one. Otherwise for a plastic tank you can't beat the T3S for performance and price.