That depends on what type of fund options you have in your 401k, and what the expense ratio (ER) is. Your fund choices are probably more expensive than the funds you could select in an IRA.
I can't tell you to save in an IRA vs saving for a down payment, that's a personal choice that is up to you.
I think you are doing the right thing contributing 6% to the 401k to get the match. If the option you are considering is just upping your 401k contribution vs starting an IRA at vanguard I say start the IRA. You will need $1,000 minimum for target date funds, and $3,000 minimum for most other index funds, so you might need to save up a little bit before you can actually start the account.
I currently have about 17k in savings right now, I want to put something in an IRA so I can start building my retirement fun but I just wanted opinions on what is better between raising 401k contribution or starting an IRA and leaving the 401k at 6%
Right, frugalnacho is saying that it depends on your investment options in the 401k (you probably can't change these) vs in an IRA you open somewhere (here you have more choice, if you choose someone with low expense ratios and fees, like vanguard). A different trade-off is that you need a minimum to open the IRA, but once you've met the minimum you can add small amounts whenever. So you may need to accumulate a few $k before opening the IRA, but going forward you can add small amounts monthly. Increasing your 401k contributions is more painless and automatic since you only have to put in the request once, and it is contributed every payday.
So, if choices in your 401k are good (low fees and expense ratios for the investments you want), it's easier to increase that. If choices are not as good, capture the employer match, then contribute to an IRA with better choices, up to the max. Then switch back to your 401k if you still have money to invest.
You are trying to find the best deal at each step on a hierarchy. Employer match outweighs poor expense ratios. After that is exhausted, low fees are better than high fees. After that space is filled, higher fees with tax advantages is better than no tax advantages.