this is exactly why I am considering choosing Open-E over OpenFiler. I had the same issue with OF, although my reads were significantly slower then the write operations.
My RAID boxes do certainly exceed the GBit perofrmance both in reads and writes. Both of them are in the 170s MB/sec. range. It may be the case that on iSCSI systems the reads are always slower than writes and I maybe just can't see it since I have a bandwidth cap at the switch level performance. I have noticed that with each distro I tried and I think that this is causes by ietd itself.
What is the hardware of your server? When I started out with iSCSI I first toll an very aged Dell PE 1650 and that clearly had its limits. Then I switched to a slightly newer PE 1750 with two 2.4 GHz Xeon CPUs and the performance immediately went to full GBit speed on writes but still was at 60 MB/sec on reads on OpenFiler. Then I installed Open-E and all the sudden, both read and write performance were equal.
Areca ARC-1261ML / 16 channel SATA
16 x 1TB Western Digital green power
Quad port Intel PCI Express server adapter
Running bonding, setup as round-robin (I'm having too many problems with LACP)
Oh yeah, I forgot to mention. Like you, I also notice a large difference in iSCSI performance when using OpenFiler. This despite using the same hardware and both being based on kernel 2.6.25.
Total write bandwidth for 4 clients: 350MB/sec
Total read bandwidth for 4 clients: 112MB/sec
That is using the same round-robin bonding as I do in Open-E.