DJP iPath DJ-UBS Commodity Index TR ETN 3.2B
AMJ JPMorgan Alerian MLP Index ETN 2.6B
VXX iPath S&P 500 VIX Short-Term Futures ETN 1.4B
RJI ELEMENTS Rogers Intl Commodity ETN 919M
VXZ iPath S&P 500 VIX Mid-Term Futures ETN 788M
INP iPath MSCI India Index ETN 719M

ETNs do trade like ETFs which makes your investment very liquid. Your risk in the investment is the credit of JP Morgan as you do not actually own anything but a promise from them to track the performance of the Master Limited Partnerships (MLP) energy sector. Master Limited Partnerships do not fit well in an ETF because you would need to receive a K1 each year for gains or losses, possibly affecting your personal tax return. Because an ETN is a note rather than an investment directly into the partnerships, you get the returns (good or bad) and pass on any tax consequences (you may get a 1099). Being that it is in an IRA for you, maybe that is not a big deal. Is it safe? Look at it this way: JP Morgan now owes you money and your rate of interest is based on the returns of the Energy MLP index. IF JPM goes out of business, you will get 0 back. So, for the security of your investment you have to look at the credit quality of JPM.

I did a quick search for Energy MLPs and did not find an ETF. There was an article at Seeking Alpha by a writer that described your ETN as an ETF. Blind leading the blind there!! If you want an energy ETF check out ishares.com and look over their energy ETFs. Vanguard has a diversified energy ETF as well. These two companies are the BIG players in ETFs thus can bring the volume and assets under management to give you a better trade.

Hope this helped.

From the JPM site:

Benefits of investing in the JPMorgan Alerian MLP Index ETN

Exposure to a portfolio of energy MLPs through a single investment.
Quarterly coupons based on the cash distributions, if any, paid on the MLPs in the Index, less fees.
No K-1 forms will be received by investors as a result of their investment in the ETNs. The coupons are reported as ordinary income on Form 1099.
The ETNs trade on the NYSE, Arca.

Main risks in the ETNs

The ETNs may result in a loss.
The ETNs are exposed to the credit risk of JPMorgan Chase & Co.
The ETNs may not have an active trading market and may not continue to be listed over their term.
The payment at maturity or upon early repurchase of the ETNs will be based on the VWAP Level of the Index and not on the closing level of the Index. The VWAP Level of the Index will most likely differ from the closing level of the Index or the IIV.
The coupon payments on the ETNs will be variable and may be zero. The Accrued Tracking Fee reduces the potential coupons and/or the payment at maturity or upon early repurchase.
The Issuer’s obligation to repurchase the ETNs is on a weekly basis, and is subject to substantial minimum size restrictions.
You will not know how much you will receive upon early repurchase at the time that you elect we repurchase your ETNs.